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Synonyms

ominous

American  
[om-uh-nuhs] / ˈɒm ə nəs /

adjective

  1. portending evil or harm; foreboding; threatening; inauspicious.

    an ominous bank of dark clouds.

  2. indicating the nature of a future event, for good or evil; having the significance of an omen; being a portent.

    Some of these events were immediately ominous, while others only later revealed themselves as such.


ominous British  
/ ˈɒmɪnəs /

adjective

  1. foreboding evil

  2. serving as or having significance as an omen

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

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: 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.

Other Word Forms

Etymology

Origin of ominous

First recorded in 1580–90; from Latin ōminōsus “portentous,” equivalent to ōmin- (stem of ōmen ) + -ōsus; see origin at omen, -ous

Explanation

If something looks or sounds ominous, be careful: a threat or an unpleasant event is at hand. If you see an ominous frown on your boss's face, you're in trouble! Ominous, and the related word omen both come from the 16th century Latin word ōmen "foreboding." However, unlike omen, which is a sign of something good or bad to come, ominous always describes something unpleasant or threatening. If the future looks ominous, you've got nothing to look forward to. Figuratively, an ominous sky or ominous clouds promise rain or a storm.

Keep Reading on Vocabulary.com

Vocabulary lists containing ominous

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Ominous headlines and abrupt u-turns about trade wars and actual wars make executives more cautious too.

From The Wall Street Journal • Apr. 1, 2026

More: Ominous ‘Hindenburg Omen’ spotted in U.S. stock market.

From MarketWatch • Feb. 10, 2026

Ominous clouds gathered on Wall Street this week—and may have passed just as quickly.

From Barron's • Nov. 14, 2025

Ominous murmurings in the dark are heard off camera.

From Seattle Times • Apr. 5, 2024

He would have been right, too, if the goddess Diana had simply been plopped in the middle of an Ominous Landscape.

From "The Hidden Gallery" by Maryrose Wood

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