Adjective ominous has 2 senses
- baleful, forbidding, menacing, minacious, minatory, ominous, sinister, threatening, ugly - threatening or foreshadowing evil or tragic developments; "a baleful look"; "forbidding thunderclouds"; "his tone became menacing"; "ominous rumblings of discontent"; "sinister storm clouds"; "a sinister smile"; "his threatening behavior"; "ugly black clouds"; "the situation became ugly"
Antonym: unalarming (indirect, via alarming)
- ill, inauspicious, ominous - presaging ill-fortune; "ill omens"; "ill predictions"; "my words with inauspicious thunderings shook heaven"- P.B.Shelley; "a dead and ominous silence prevailed"; "a by-election at a time highly unpropitious for the Government"
Antonym: propitious (indirect, via unpropitious)
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