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Synonyms

lucid

American  
[loo-sid] / ˈlu sɪd /

adjective

  1. easily understood; completely intelligible or comprehensible.

    a lucid explanation.

    Synonyms:
    obvious, evident, understandable, plain
    Antonyms:
    obscure
  2. characterized by clear perception or understanding; rational or sane.

    a lucid moment in his madness.

    Synonyms:
    reasonable, sound
    Antonyms:
    irrational
  3. shining or bright.

    Synonyms:
    luminous, radiant
    Antonyms:
    dim
  4. clear; pellucid; transparent.

    Synonyms:
    limpid
    Antonyms:
    obscure

lucid British  
/ ˈluːsɪd /

adjective

  1. readily understood; clear

  2. shining or glowing

  3. psychiatry of or relating to a period of normality between periods of insane or irresponsible behaviour

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • lucidity noun
  • lucidly adverb
  • lucidness noun
  • nonlucid adjective
  • nonlucidly adverb
  • nonlucidness noun
  • unlucid adjective
  • unlucidly adverb
  • unlucidness noun

Etymology

Origin of lucid

First recorded in 1575–85; from Latin lūcidus, equivalent to lūc- (stem of lūx light 1 ) + -idus -id 4

Explanation

Something that's lucid is clear and understandable. Lucid writing is important in journalism, so that readers easily get the point of the article they're reading. When what you write or say is lucid, it's straightforward and its meaning is crystal clear. You can also use the adjective lucid to describe your mind or thoughts when you're thinking in a rational, sensible way: "I was worried about my grandmother's confusion yesterday, but she seems really lucid today." Another meaning is "translucent," or "letting light shine through" — which makes sense since lucid comes from the Latin lucidus, "light or clear," with its root of lux, "light."

Keep Reading on Vocabulary.com

Vocabulary lists containing lucid

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The second thing to say is that AOC’s actual response to the question, once she finally got there, was entirely lucid and reasonable.

From Salon • Feb. 22, 2026

Karen Konkoly, the study's lead author and a postdoctoral researcher in Paller's Cognitive Neuroscience Laboratory, said one of the biggest surprises was how strongly the cues influenced dreams even when participants were not lucid.

From Science Daily • Feb. 15, 2026

Maybe the 93-year-old was more lucid than I thought.

From Slate • Dec. 1, 2025

He had a lucid conversation with the ER doctor that night, who agreed to take him off the medications.

From The Wall Street Journal • Nov. 20, 2025

“The doctors think it possible, but daren’t yet say for certain. It should be apparent in a few days’ time when he is rested; then we will see whether he is lucid again.”

From "Vincent and Theo: The Van Gogh Brothers" by Deborah Heiligman