- portending evil or harm; foreboding; threatening; inauspicious: an ominous bank of dark clouds.
- 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.
- foreboding evil
- serving as or having significance as an omen
adv.1590s, from ominous + -ly (2). In earliest use, “of good omen, auspicious;” meaning “of evil omen” first attested 1640s, in Milton. adj.1580s, from Latin ominosus “full of foreboding,” from omen (genitive ominis) “foreboding” (see omen). Related: Ominousness.