WordReference Random House Learner's Dictionary of American English © 2026
om•i•nous /ˈɑmənəs/USA pronunciation
adj.
om•i•nous•ness, n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2026- foreboding;
threatening:ominous black clouds.
om•i•nous•ness, n. [uncountable]
om•i•nous
(om′ə nəs),USA pronunciation adj.
om′i•nous•ly, adv.
om′i•nous•ness, n.
- portending evil or harm;
foreboding;
threatening;
inauspicious:an ominous bank of dark clouds. - having the significance of an omen.
- Latin ōminōsus portentous, equivalent. to ōmin- (stem of ōmen) omen + -ōsus -ous
- 1580–90
om′i•nous•ness, n.
- Ominous, portentous, threatening, menacing, fateful are adjectives describing that which forebodes a serious, significant, and often harmful outcome. Ominous, derived from omen "a predictor of outcomes,'' usually suggests evil or damaging eventualities:ominous storm clouds; an ominous silence.Portentous, although it may suggest evil results, often stresses a momentous or very important outcome:a portentous moment in history; a portentous escalation of hostilities.Threatening may suggest calamity or great harm but sometimes mere unpleasantness:a threatening rumble from the volcano; A threatening look from his brother caused him to quickly change the subject.Menacing always suggests serious damage as an outcome:a disease menacing the entire population; He advanced with a menacing swagger.Fateful most often stresses the great or decisive importance of what it describes:a fateful encounter between two future leaders; a fateful day that changed our world.