Adjective portentous has 3 senses
- portentous, prodigious - of momentous or ominous significance; "such a portentous...monster raised all my curiosity"- Herman Melville; "a prodigious vision"
Antonyms: insignificant, unimportant (indirect, via significant)
- fateful, foreboding, portentous - of ominous significance
Antonym: unprophetic (indirect, via prophetic)
- grandiloquent, overblown, pompous, pontifical, portentous - puffed up with vanity; "a grandiloquent and boastful manner"; "overblown oratory"; "a pompous speech"; "pseudo-scientific gobbledygook and pontifical hooey"- Newsweek
Antonym: unpretentious (indirect, via pretentious)
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