Breadcrumb Home > Dictionary > Index L Cite 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. January 2021 Current Events: US News The Holocaust (1933–1945) Chinese New Year History, Meaning, and Celebrations Noble Titles and Ranks in a Monarchy The 5 Best Air Purifiers of 2020 Inaugural Trivia Related Content Daily Word Quiz: obviate Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language