/ Dictionary / Index L loon: Meaning and Definition of Find definitions for: loon Pronunciation: (ln), [key] — n. any of several large, short-tailed, web-footed, fish-eating diving birds of the genus Gavia, of the Northern Hemisphere. loon Pronunciation: (ln), [key] — n. a crazy or simple-minded person. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: loon (Thesaurus) looming looney Related Content Daily Word Quiz: arboreal Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language