rad·i·cal

(răd′ĭ-kəl)

adj.

1. Arising from or going to a root or source; basic: proposed a radical solution to the problem.

2. Departing markedly from the usual or customary; extreme or drastic: a radical change in diet.

3. Relating to or advocating fundamental or revolutionary changes in current practices, conditions, or institutions: radical politics; a radical political theorist.

4. Medicine Relating to or being surgery that is extreme or drastic in an effort to eradicate all existing or potential disease: radical hysterectomy.

5. Linguistics Of or being a root: a radical form.

6. Botany

a. Of, relating to, or arising from a root: radical hairs.

b. Arising from the base of a stem or from a below-ground stem or rhizome: radical leaves.

7. Slang Excellent; wonderful.

1. One who advocates fundamental or revolutionary changes in current practices, conditions, or institutions: radicals seeking to overthrow the social order.

2. Mathematics The root of a quantity as indicated by the radical sign.

3. Symbol R An atom or a group of atoms with one unpaired electron.

4. Linguistics See root¹.

a. Any of the basic Chinese characters that are combined to form more complex characters.

b. Any of the traditional set of basic strokes or groups of strokes that make up Chinese characters and are used to classify and organize them in dictionaries.

[Middle English, of a root, from Late Latin rādīcālis, having roots, from Latin rādīx, rādīc-, root; see wrād- in Indo-European roots.]

rad′i·cal·ly adv.

rad′i·cal·ness n.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

radical

(ˈrædɪkəl)

adj

1. of, relating to, or characteristic of the basic or inherent constitution of a person or thing; fundamental: a radical fault.

2. concerned with or tending to concentrate on fundamental aspects of a matter; searching or thoroughgoing: radical thought; a radical re-examination.

3. (Government, Politics & Diplomacy) favouring or tending to produce extreme or fundamental changes in political, economic, or social conditions, institutions, habits of mind, etc: a radical party.

4. (Medicine) med (of treatment) aimed at removing the source of a disease: radical surgery.

5. slang chiefly US very good; excellent

6. (Botany) of, relating to, or arising from the root or the base of the stem of a plant: radical leaves.

7. (Mathematics) maths of, relating to, or containing roots of numbers or quantities

8. (Linguistics) linguistics of or relating to the root of a word

9. (Government, Politics & Diplomacy) a person who favours extreme or fundamental change in existing institutions or in political, social, or economic conditions

10. (Mathematics) maths a root of a number or quantity, such as ³√5, √x

11. (Chemistry) chem

a. short for free radical

b. another name for group¹⁰

12. (Linguistics) linguistics another word for root¹⁹

13. (Linguistics) (in logographic writing systems such as that used for Chinese) a part of a character conveying lexical meaning

[C14: from Late Latin rādīcālis having roots, from Latin rādix a root]

ˈradicalness n

Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

rad•i•cal

(ˈræd ɪ kəl)

adj.

1. of or going to the root or origin; fundamental.

2. thoroughgoing or extreme: a radical change in company policy.

3. favoring drastic political, economic, or social reforms.

4. existing inherently in a thing or person: radical defects of character.

5. Math.

a. pertaining to or forming a root.

b. denoting or pertaining to the radical sign.

c. irrational (def. 4b).

6. of or pertaining to the root of a word.

7. Bot. of or arising from the root or the base of the stem.

8. Slang. great; marvelous; wonderful.

9. a person who holds or follows strong convictions or extreme principles; extremist.

10. a person who advocates fundamental political, economic, and social reforms by direct and often uncompromising methods.

11. Math.

a. a quantity expressed as a root of another quantity.

b. radical sign.

12. Chem.

a. group (def. 3).

b. free radical.

13. root ¹ (def. 10).

[1350–1400; Middle English < Late Latin rādīcālis having roots < Latin rādīc- (s. of rādīx) root¹]

rad·i·cal

(răd′ĭ-kəl)

1. A root, such as √2, especially as indicated by a radical sign (√).

2. A group of atoms that behaves as a unit in chemical reactions and is often not stable except as part of a molecule. The hydroxyl, ethyl, and phenyl radicals are examples. Radicals are unchanged by chemical reactions.

The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

radical

A group of atoms forming part of many molecules. They are very reactive as they have an incomplete electron structure.

ThesaurusAntonymsRelated WordsSynonymsLegend:

Noun	1.	radical - (chemistry) two or more atoms bound together as a single unit and forming part of a molecule chemical group, group chemical science, chemistry - the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions building block, unit - a single undivided natural thing occurring in the composition of something else; "units of nucleic acids" acyl, acyl group - any group or radical of the form RCO- where R is an organic group; "an example of the acyl group is the acetyl group" alcohol group, alcohol radical - the chemical group -OH aldehyde group, aldehyde radical - the chemical group -CHO alkyl, alkyl group, alkyl radical - any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons allyl, allyl group, allyl radical - the univalent unsaturated organic radical C3H5; derived from propylene amino, amino group - the radical -NH2 amyl - a hydrocarbon radical that occurs in many organic compounds azido group, azido radical - the univalent group N3- derived from hydrazoic acid azo group, azo radical - the bivalent group -N=N- united to two hydrocarbon groups benzyl, benzyl group, benzyl radical - the univalent radical derived from toluene benzoyl group, benzoyl radical - the univalent radical derived from benzoic acid molecule - (physics and chemistry) the simplest structural unit of an element or compound arsenic group, cacodyl group, cacodyl radical, cacodyl - the univalent group derived from arsine carbonyl group - the bivalent radical CO carboxyl, carboxyl group - the univalent radical -COOH; present in and characteristic of organic acids chromophore - the chemical group that gives color to a molecule cyanide group, cyanide radical, cyano group, cyano radical - the monovalent group -CN in a chemical compound glyceryl - a trivalent radical derived from glycerol by removing the three hydroxyl radicals hydrazo group, hydrazo radical - the bivalent group -HNNH- derived from hydrazine hydroxyl, hydroxyl group, hydroxyl radical - the monovalent group -OH in such compounds as bases and some acids and alcohols ketone group - a group having the characteristic properties of ketones methylene, methylene group, methylene radical - the bivalent radical CH2 derived from methane propyl, propyl group, propyl radical - the monovalent organic group C3H7- obtained from propane butyl - a hydrocarbon radical (C4H9) nitro group - the group -NO3 nitrite - the radical -NO2 or any compound containing it (such as a salt or ester of nitrous acid) uranyl, uranyl group, uranyl radical - the bivalent radical UO2 which forms salts with acids vinyl, vinyl group, vinyl radical - a univalent chemical radical derived from ethylene
	2.	radical - an atom or group of atoms with at least one unpaired electron; in the body it is usually an oxygen molecule that has lost an electron and will stabilize itself by stealing an electron from a nearby molecule; "in the body free radicals are high-energy particles that ricochet wildly and damage cells" free radical atom - (physics and chemistry) the smallest component of an element having the chemical properties of the element
	3.	radical - a person who has radical ideas or opinions individual, mortal, person, somebody, someone, soul - a human being; "there was too much for one person to do" anarchist, syndicalist, nihilist - an advocate of anarchism Bolshevik, bolshie, bolshy, Marxist, red - emotionally charged terms used to refer to extreme radicals or revolutionaries extremist - a person who holds extreme views leveler, leveller - a radical who advocates the abolition of social distinctions revolutionary, revolutionist, subversive, subverter - a radical supporter of political or social revolution terrorist - a radical who employs terror as a political weapon; usually organizes with other terrorists in small cells; often uses religion as a cover for terrorist activities Trotskyist, Trotskyite, Trot - radicals who support Trotsky's theory that socialism must be established throughout the world by continuing revolution Wobbly - a member of the Industrial Workers of the World young Turk - a young radical who agitates for reform
	4.	radical - (mathematics) a quantity expressed as the root of another quantity quantity, measure, amount - how much there is or how many there are of something that you can quantify math, mathematics, maths - a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement
	5.	radical - a character conveying the lexical meaning of a logogram grapheme, graphic symbol, character - a written symbol that is used to represent speech; "the Greek alphabet has 24 characters" ideogram, ideograph - a graphic character that indicates the meaning of a thing without indicating the sounds used to say it; "Chinese characters are ideograms"
	6.	radical - (linguistics) the form of a word after all affixes are removed; "thematic vowels are part of the stem" root word, stem, root, theme, base linguistics - the scientific study of language descriptor, form, signifier, word form - the phonological or orthographic sound or appearance of a word that can be used to describe or identify something; "the inflected forms of a word can be represented by a stem and a list of inflections to be attached"
Adj.	1.	radical - (used of opinions and actions) far beyond the norm; "extremist political views"; "radical opinions on education"; "an ultra conservative" extremist, ultra immoderate - beyond reasonable limits; "immoderate laughter"; "immoderate spending"
	2.	radical - markedly new or introducing radical change; "a revolutionary discovery"; "radical political views" revolutionary new - not of long duration; having just (or relatively recently) come into being or been made or acquired or discovered; "a new law"; "new cars"; "a new comet"; "a new friend"; "a new year"; "the New World"
	3.	radical - arising from or going to the root or source; "a radical flaw in the plan" basic - pertaining to or constituting a base or basis; "a basic fact"; "the basic ingredients"; "basic changes in public opinion occur because of changes in priorities"
	4.	radical - of or relating to or constituting a linguistic root; "a radical verb form" linguistics - the scientific study of language
	5.	radical - especially of leaves; located at the base of a plant or stem; especially arising directly from the root or rootstock or a root-like stem; "basal placentation"; "radical leaves" basal phytology, botany - the branch of biology that studies plants cauline - especially of leaves; growing on a stem especially on the upper part of a stem; "cauline leaves"

radical

adjective

1. extreme, complete, entire, sweeping, violent, severe, extensive, wide-ranging, excessive, thorough, drastic, rigorous, far-reaching, draconian periods of radical change

2. revolutionary, reforming, extreme, militant, progressive, left-wing, extremist, reformist, fanatical political tension between radical and conservative politicians

3. fundamental, natural, basic, essential, native, constitutional, organic, profound, innate, deep-seated, thoroughgoing, hard-wired the radical differences between them
fundamental minor, token, trivial, superficial, insignificant

noun

1. extremist, revolutionary, militant, reformer, fanatic, left-winger, zealot, revisionist a former left-wing radical who was involved with the civil rights movement
extremist conservative, moderate, reactionary

Quotations
"A radical is a man with both feet firmly planted in the air" [Franklin D. Roosevelt radio broadcast]

Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002

radical

adjective

1. Arising from or going to the root or source:

basal, basic, foundational, fundamental, original, primary, underlying.

2. Holding especially political views that deviate drastically and fundamentally from conventional or traditional beliefs:

extreme, extremist, fanatic, fanatical, rabid, revolutionary, ultra.

Slang: far-out.

noun

One who holds extreme views or advocates extreme measures:

extremist, fanatic, revolutionary, revolutionist, ultra, zealot.

Translations

أساسيشامِل، جَذْريشَخْص راديكالي: مُتَطَرِّفمُتَطَرِّف

extrémníradikálradikálnízákladnízásadní

ekstremistgennemgribendegrundlæggenderadikalyderliggående

radikal Radikale drastisch fundamental

radical fundamental

juurimullistavaperusperusteellinenradikaali

radicalradicalaireradicale super fondamental

gyökeresradikális

djúptækur, róttækurgrundvallar-róttæklingurróttækur

radicaleradicalicofondamentale

部首

radikalas

būtiskskrasspamatīgs

radikal venstreorientert person

radical

радикал ключ корень

extrémnyzásadný

asıl köklü köktenci radikalradikal kimse

基本的根本的激进分子激进的部首

radical

[ˈrædɪkəl]

A. ADJ

1. (Pol) [idea, organization] → radical; [person] → radical, de ideas radicales
she's very radical → es muy radical → es de or tiene ideas muy radicales
a radical feminist → una feminista radical

2. (= extreme, major) [change, measures, surgery, reduction] → radical; [advance] → innovador

B. N (Pol) → radical mf (Bot, Chem, Ling, Math) → radical m

Collins Spanish Dictionary - Complete and Unabridged 8th Edition 2005 © William Collins Sons & Co. Ltd. 1971, 1988 © HarperCollins Publishers 1992, 1993, 1996, 1997, 2000, 2003, 2005

radical

[ˈrædɪk^əl]

adj

[change, reform, overhaul] → radical(e)

[plan, proposal, concept, measure, idea] → radical(e)

[politician, party, wing, group, feminist] → radical(e)

[surgery] → radical(e)

(US) (= excellent) → d'enfer

(= person) → radical(e) m/f

(CHEMISTRY) (also free radical) → radical m libre

radical

adj

(= basic) → fundamental, Grund-; difference, error → fundamental; (= extreme) change, reform → radikal, grundlegend; rethinking, re-examination → total; measures → einschneidend, radikal; reduction → radikal, fundamental, rigoros

(Pol) person, organization, idea → radikal; attitude → radikal, rigoros; to effect a radical cure → eine Radikalkur machen; radical surgery → Radikalchirurgie f

(Math) → Wurzel-; a radical expression → eine Wurzel

(Bot) leaves → bodenständig

n (Pol) → Radikale(r) mf; (Math, Gram) → Wurzel f; (in Chinese) → Radikal m; (Chem) → Radikal nt

radical

radical fundamentalist

adj → radikalfundamentalistisch

radical Islamic

adj → radikalislamisch

Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007

radical

[ˈrædɪk/əl]

1. adj → radicale

2. n

a. (person) → radicale m/f

b. (Math, Chem) → radicale m

radical

(ˈrӕdikəl) adjective

1. relating to the basic nature of something. radical faults in the design.

2. thorough; complete. radical changes.

3. wanting or involving great or extreme political, social or economic changes.

noun

a person who wants radical political changes.

ˈradically adverb

radical

adj radical