/ Dictionary / Index L lunatic: Meaning and Definition of Find definitions for: lu•na•tic Pronunciation: (l'nu-tik), [key] — n. an insane person. a person whose actions and manner are marked by extreme eccentricity or recklessness. a person legally declared to be of unsound mind and who therefore is not held capable or responsible before the law. —adj. insane; demented; crazy. characteristic or suggestive of lunacy; wildly or recklessly foolish. designated for or used by the insane: a lunatic asylum. gaily or lightheartedly mad, frivolous, eccentric, etc.: She has a lunatic charm that is quite engaging. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: lunatic (Thesaurus) lunate lunatic fringe Related Content Daily Word Quiz: tenacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language