/ Dictionary / Index O ominous: Meaning and Definition of Find definitions for: om•i•nous Pronunciation: (om'u-nus), [key] — adj. portending evil or harm; foreboding; threatening; inauspicious: an ominous bank of dark clouds. having the significance of an omen. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ominous (Thesaurus) omicron omissible Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language