OMINOUS most nearly means:

OMINOUS means giving the impression that something bad or unpleasant is going to happen; threatening. Example: 'Dark, ominous clouds gathered before the storm.' From Latin 'omen' (a sign, especially a sign of misfortune). Synonyms: threatening, sinister, menacing, foreboding, portentous, baleful. Antonyms: encouraging, promising, auspicious, propitious, favorable. Related words: OMEN (a sign foreshadowing future events), PREMONITION (a forewarning, especially of something unpleasant), FOREBODE (to indicate beforehand, usually negative). Don't confuse with: NOMINAL (in name only); OMNIPOTENT (all-powerful — from 'omni-' meaning all, not 'omen'). The negative connotation of ominous is important — choices like 'ordinary' (neutral) or 'pleasant' (positive) cannot be correct. When you recognize a word is clearly negative or positive, you can eliminate answer choices with the opposite connotation immediately.