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Related to necessary: Necessary and sufficient


1. Needed or required: a contract complete with the necessary signatures; conditions necessary to life. See Synonyms at indispensable.
a. Unavoidably determined by prior conditions or circumstances; inevitable: the necessary results of overindulgence.
b. Logically inevitable: a necessary conclusion.
3. Required by obligation, compulsion, or convention: made the necessary apologies.
n. pl. nec·es·sar·ies
Something indispensable.

[Middle English necessarie, from Old French necessaire, from Latin necessārius, from necesse; see ked- in Indo-European roots.]
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.


1. needed to achieve a certain desired effect or result; required
2. resulting from necessity; inevitable: the necessary consequences of your action.
3. (Logic) logic
a. (of a statement, formula, etc) true under all interpretations or in all possible circumstances
b. (of a proposition) determined to be true by its meaning, so that its denial would be self-contradictory
c. (of a property) essential, so that without it its subject would not be the entity it is
d. (of an inference) always yielding a true conclusion when its premises are true; valid
e. (of a condition) entailed by the truth of some statement or the obtaining of some state of affairs. Compare sufficient2
4. (Philosophy) philosophy (in a nonlogical sense) expressing a law of nature, so that if it is in this sense necessary that all As are B, even although it is not contradictory to conceive of an A which is not B, we are licensed to infer that if something were an A it would have to be B
5. rare compelled, as by necessity or law; not free
6. the necessary informal the money required for a particular purpose
7. do the necessary informal to do something that is necessary in a particular situation
[C14: from Latin necessārius indispensable, from necesse unavoidable]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈnɛs əˌsɛr i)

adj., n., pl. -sar•ies. adj.
1. essential, indispensable, or requisite: a necessary part of the motor.
2. happening or existing by necessity; unavoidable: a necessary change in our plans.
3. acting or proceeding from compulsion or necessity; involuntary.
4. Logic.
a. (of a proposition) such that a denial of it involves a self-contradiction.
b. (of an inference or argument) such that its conclusion cannot be false if its supporting premises are true.
c. (of a condition) such that it must exist if a given event is to occur or a given thing is to exist. Compare sufficient (def. 2).
5. something necessary or requisite; necessity.
6. Chiefly New Eng. a privy or toilet.
[1300–50; Middle English < Latin necessārius unavoidable, inevitable, needful]
nec′es•sar`i•ness, n.
syn: necessary, requisite, indispensable, essential indicate something that cannot be done without. necessary refers to something needed for existence, for proper functioning, or for a particular purpose: Food is necessary for life. Sugar is a necessary ingredient in this recipe. requisite refers to something required for a particular purpose or by particular circumstances: She has the requisite qualifications for the job. indispensable means absolutely necessary to achieve a particular purpose or to complete or perfect a unit: He made himself indispensable in the laboratory. essential refers to something that is part of the basic nature or character of a thing and is vital to its existence or functioning: Water is essential to life.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


1. used with an infinitive

If it is necessary to do a particular thing, that thing must be done.

It is necessary to act fast.
It is necessary to examine the patient carefully.
2. used with 'for'

You can say that it is necessary for someone to do something.

It was necessary for me to keep active and not think about Sally.
It is necessary for management and staff to work together positively.

Be Careful!
If you use necessary in sentences like these, the subject must be it. Don't say, for example, 'She was necessary to make several calls'. Say 'It was necessary for her to make several calls'. However, in conversation and in less formal writing, people normally say 'She had to make several calls'.

See must

If one thing is necessary for another, the second thing can only happen or exist if the first one happens or exists.

Total rest is necessary for the muscle to repair itself.
Collins COBUILD English Usage © HarperCollins Publishers 1992, 2004, 2011, 2012
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.necessary - anything indispensable; "food and shelter are necessities of life"; "the essentials of the good life"; "allow farmers to buy their requirements under favorable conditions"; "a place where the requisites of water fuel and fodder can be obtained"
thing - a separate and self-contained entity
desideratum - something desired as a necessity; "the desiderata for a vacation are time and money"
must - a necessary or essential thing; "seat belts are an absolute must"
need, want - anything that is necessary but lacking; "he had sufficient means to meet his simple needs"; "I tried to supply his wants"
Adj.1.necessary - absolutely essential
obligatory - morally or legally constraining or binding; "attendance is obligatory"; "an obligatory contribution"
essential - basic and fundamental; "the essential feature"
indispensable - not to be dispensed with; essential; "foods indispensable to good nutrition"
unnecessary, unneeded - not necessary
2.necessary - unavoidably determined by prior circumstances; "the necessary consequences of one's actions"
inevitable - incapable of being avoided or prevented; "the inevitable result"
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


2. inevitable, sure, certain, unavoidable, inescapable Wastage was no doubt a necessary consequence of war.
inevitable avoidable, unnecessary
the necessary (Informal) money, means, funds, capital, cash, finances, resources, dough (informal), the readies (informal), dosh (Brit. informal), the wherewithal, wonga (slang) I could always count on her if I was a bit short of the necessary.
Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002


1. Incapable of being dispensed with:
2. Imposed on one by authority, command, or convention:
The American Heritage® Roget's Thesaurus. Copyright © 2013, 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
būtinas daiktasbūtinas reikalasneišvengiamaireikalingas
cần thiết


1. (= required) → necesario
is that really necessary?¿es eso realmente or verdaderamente necesario?
to be necessary to do sthser necesario or preciso hacer algo
is it necessary for us to go?¿es necesario or preciso que vayamos?
if necessarysi es necesario or preciso
don't do more than is necessaryno hagas más de lo necesario
do whatever (is) necessary to find himhaz todo lo posible para encontrarlo
when/where necessarycuando/donde sea necesario or preciso
2. (= inevitable) [consequence, conclusion] → inevitable
a necessary evilun mal necesario
B. N
1. (= what is required) the necessarylo necesario
I'll do the necessaryharé lo que haga falta, haré lo que sea necesario
2. (= money) have you got the necessary?¿tienes la pasta?
3. necessaries (= essentials) the necessaries of lifelas necesidades básicas (de la vida)
there are shops nearby for all the necessarieshay tiendas cerca para todo lo necesario
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


[ˈnɛsəsəri] adj
(= required) → nécessaire
Are we teaching students the necessary skills? → Enseignons-nous aux étudiants les compétences nécessaires?
necessary for → nécessaire pour
the colours necessary for perfect camouflage → les couleurs nécessaires pour un parfait camouflage
longer than necessary → plus longtemps que nécessaire
I don't want to stay longer than necessary → Je ne veux pas rester plus longtemps que nécessaire.
it is necessary to do sth (= we must) → il est nécessaire de faire qch
It is necessary to examine this assertion → Il est nécessaire d'examiner cette assertion.
it may be necessary to do this → il faudra peut-être faire ça
It may be necessary to buy a new cooker → Il faudra peut-être acheter une nouvelle cuisinière.
it may be necessary for sb to do this → il faudra peut-être que qn fasse ça
It may be necessary for us to sell the house → Il faudra peut-être que nous vendions la maison.
if necessary → si nécessaire
If necessary, the airship can stay up there for days → Si nécessaire, l'aéronef peut rester en l'air pendant des jours.
when necessary → lorsque c'est nécessaire
The army needs men who are willing to fight, when necessary → L'armée a besoin d'hommes prêts à combattre, lorsque c'est nécessaire.
where necessary → le cas échéant
All the rigging had been examined, and renewed where necessary → Toutes les amarres ont été inspectées et, le cas échéant, remplacées.
[connection, consequence] → nécessaire
Collins English/French Electronic Resource. © HarperCollins Publishers 2005


notwendig, nötig, erforderlich (to, for für); it is necessary to …man muss …; is it really necessary for me to come too?muss ich denn wirklich auch kommen?; it’s not necessary for you to comeSie brauchen nicht zu kommen; it is necessary for him to be therees ist nötig or notwendig, dass er da ist, er muss da sein; all the necessary qualificationsalle erforderlichen Qualifikationen; necessary conditionVoraussetzung f; (Logic) → notwendige Voraussetzung; to be/become necessary to somebodyjdm unentbehrlich sein/werden; to make it necessary for somebody to do somethinges erforderlich machen, dass jd etw tut; if/when necessarywenn nötig, nötigenfalls; where necessarywo nötig; you were rude to him, was that necessary?du warst grob zu ihm, war das denn notwendig or nötig?; that won’t be necessarydas wird nicht nötig sein; to make the necessary arrangementsdie erforderlichen or notwendigen Maßnahmen treffen; to do everything necessary, to do whatever is necessaryalles Nötige tun; to do no more than is (strictly) necessarynicht mehr tun, als unbedingt notwendig or nötig ist; good food is necessary to healthgutes Essen ist für die Gesundheit notwendig
(= unavoidable) conclusion, change, resultunausweichlich; we drew the necessary conclusionswir haben die entsprechenden Schlüsse daraus gezogen; a necessary evilein notwendiges Übel
(inf: = what is needed) the necessarydas Notwendige; will you do the necessary?wirst du das Notwendige or Nötige erledigen?
(inf: = money) the necessarydas nötige Kleingeld
usu pl the necessary or necessariesdas Notwendige
Collins German Dictionary – Complete and Unabridged 7th Edition 2005. © William Collins Sons & Co. Ltd. 1980 © HarperCollins Publishers 1991, 1997, 1999, 2004, 2005, 2007


1. adj (gen) → necessario/a; (result, effect) → inevitabile
a necessary evil → un male necessario
is it necessary to make so much noise? → è proprio necessario or indispensabile far tanto rumore?
it is necessary for you to go or that you go → è necessario che or bisogna che tu vada
don't do more than is necessary → non fare più del necessario
if necessary → se necessario
the necessary qualifications (for) → i requisiti necessari (per)
necessary to health → necessario/a alla salute
2. n (fam) (what is needed) to do the necessaryfare il necessario
the necessary (money) → i quattrini
Collins Italian Dictionary 1st Edition © HarperCollins Publishers 1995


(ˈnesisəri) adjective
needed; essential. Is it necessary to sign one's name?; I shall do all that is necessary.
ˌnecesˈsarily (-ˈse-) adverb
necessitate (niˈsesiteit) verb
to make necessary. Re-building the castle would necessitate spending a lot of money.
necessity (niˈsesəti) plural neˈcessities noun
something needed or essential. Food is one of the necessities of life.
Kernerman English Multilingual Dictionary © 2006-2013 K Dictionaries Ltd.


ضَرُورِيّ nezbytný nødvendig notwendig απαραίτητος necesario välttämätön nécessaire potreban necessario 必要な 필요한 nodig nødvendig konieczny necessário обязательный nödvändig จำเป็น gerekli cần thiết 必要的
Multilingual Translator © HarperCollins Publishers 2009


n. necesidad;
a. necesario-a, indispensable;
It is ___Es necesario;
what is ___lo necesario;
whatever is ___lo que sea necesario.
English-Spanish Medical Dictionary © Farlex 2012
References in classic literature ?
Thus disease and health are naturally present in the body of an animal, and it is necessary that either the one or the other should be present in the body of an animal.
It is not necessary that every substance, receptive of such qualities, should be either black or white, cold or hot, for something intermediate between these contraries may very well be present in the subject.
For it is not necessary that a subject receptive of the qualities should always have either the one or the other; that which has not yet advanced to the state when sight is natural is not said either to be blind or to see.
To live the same family life as his father and forefathers--that is, in the same condition of culture--and to bring up his children in the same, was incontestably necessary. It was as necessary as dining when one was hungry.
It was necessary to look after the comfort of his sister-in-law and her children, and of his wife and baby, and it was impossible not to spend with them at least a short time each day.
The last clause of the eighth section of the first article of the plan under consideration authorizes the national legislature "to make all laws which shall be NECESSARY and PROPER for carrying into execution THE POWERS by that Constitution vested in the government of the United States, or in any department or officer thereof"; and the second clause of the sixth article declares, "that the Constitution and the laws of the United States made IN PURSUANCE THEREOF, and the treaties made by their authority shall be the SUPREME LAW of the land, any thing in the constitution or laws of any State to the contrary notwithstanding."
They are only declaratory of a truth which would have resulted by necessary and unavoidable implication from the very act of constituting a federal government, and vesting it with certain specified powers.
It cannot have escaped those who have attended with candor to the arguments employed against the extensive powers of the government, that the authors of them have very little considered how far these powers were necessary means of attaining a necessary end.
Is the power of declaring war necessary? No man will answer this question in the negative.
SINCE it is now evident of what parts a city is composed, it will be necessary to treat first of family government, for every city is made up of families, and every family [1253b] has again its separate parts of which it is composed.
It was necessary, therefore, to Moses that he should find the people of Israel in Egypt enslaved and oppressed by the Egyptians, in order that they should be disposed to follow him so as to be delivered out of bondage.
It is necessary, therefore, if we desire to discuss this matter thoroughly, to inquire whether these innovators can rely on themselves or have to depend on others: that is to say, whether, to consummate their enterprise, have they to use prayers or can they use force?