Breadcrumb Home > Dictionary > Index L loony: Meaning and Definition of Find definitions for: loon•y Pronunciation: (l'nē), [key] — adj., n., pl. loon•i•er, loon•i•est, loon•ies. —adj. lunatic; insane. extremely or senselessly foolish. —n. a lunatic. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: loony (Thesaurus) looney loony bin TrendingHere are the facts and trivia that people are buzzing about. Jewish Holidays, 2010-2030 (A.M. 5770-5791) Western Christian Holidays, 2010-2030 12 Steps to a New Year New Year's Resolution to Slim Down? Martin Luther King Speeches Books of the Bible: Old Testament Books in Order ✖ Related Content Daily Word Quiz: contretemps Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language