Also found in: Thesaurus, Medical, Encyclopedia.


1. Clearly expressed; easily understood: a lucid analysis of the problem.
2. Thinking or expressing oneself clearly, especially between periods of confusion; clearheaded: The feverish patient was lucid now and then.
3. Brightly lit; luminous: "A lucid yellow moon was rising when Luke wheeled his truck to the curb and got out" (Willie Morris).
4. Clear; transparent: a lucid stream.

[Latin lūcidus, from lūcēre, to shine; see leuk- in Indo-European roots.]

lu·cid′i·ty, lu′cid·ness n.
lu′cid·ly adv.
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.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.lucidness - free from obscurity and easy to understand; the comprehensibility of clear expression
comprehensibility, understandability - the quality of comprehensible language or thought
monosemy - having a single meaning (absence of ambiguity) usually of individual words or phrases
focus - maximum clarity or distinctness of an idea; "the controversy brought clearly into focus an important difference of opinion"
clearcutness, preciseness - clarity as a consequence of precision
perspicuity, perspicuousness, plainness - clarity as a consequence of being perspicuous
unambiguity, unequivocalness - clarity achieved by the avoidance of ambiguity
explicitness - clarity as a consequence of being explicit
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.


1. The quality of being clear and easy to perceive or understand:
2. A healthy mental state:
lucidity, mind, reason, saneness, sanity, sense (often used in plural), soundness, wit (used in plural).
Slang: marble (used in plural).
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.


n. lucidez, claridad mental.
English-Spanish Medical Dictionary © Farlex 2012
References in classic literature ?
With a body of which he was scarcely aware, for even the pain had been exhausted out of it, and with a bright clear brain that accommodated him to a quiet ecstasy of sheer lucidness of thought, he lay back on the lurching litter and watched the fading of the passing world, beholding for the last time the breadfruit tree before the devil- devil house, the dim day beneath the matted jungle roof, the gloomy gorge between the shouldering mountains, the saddle of raw limestone, and the mesa of black volcanic sand.
He was in and out of lucidness. I went downstairs and bought him a can of Coke and a cup of coffee.
pting oan's ar " Sister Monica Joan's future is unclear as she dips in and out of lucidness.