DictionaryominousWarning of trouble
adjective

ominous

AH-mi-nuhs/ˈɑːmɪnəs/

Suggesting that something bad or threatening may happen.

Ominous clouds gather over the lake as we head home.

A dark, low storm cloud looms over a small unoccupied house, with a nearby tree bending in the rising wind: clear warning of danger before any damage has occurred.
Etymology

Literally “full of foreboding,” ominous originally meant conveying an omen. Its meaning narrowed to threatening signs, so it now suggests coming harm rather than either good or bad fortune.

In context

Rob Freeman0:00
looks like we're in for a real storm here look at those clouds very ominous looking towards the river but the storm is kind of coming right to us
Ominous Storm Front - Tornado Warnings - May 29, 2016

More examples

  • The engine makes an ominous rattling sound.
  • An ominous silence follows the doctor's question.
  • Falling sales are an ominous sign for the company.

Forms

ominous

ominously adverb — In a way that suggests approaching trouble.

ominousness noun — The quality of suggesting approaching trouble.

Similar words

foreboding
Emphasizes a fearful sense that something bad is coming.
threatening
Suggests more direct or immediate danger, not merely warning signs.
sinister
Often suggests hidden evil or harmful intent, not just trouble.