/ Dictionary / Index F fly-by-night: Meaning and Definition of Find definitions for: fly-by-night Pronunciation: (flī'bī-nīt"), [key] — adj. not reliable or responsible, esp. in business; untrustworthy: a fly-by-night operation. not lasting; brief; impermanent; transitory: a fly-by-night theater. —n. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fly-by-night (Thesaurus) flyby fly-by-wire Related Content Daily Word Quiz: censure Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language