7
significative(adjective, importance, valuable, main, notable)
7
unlucky(adjective, black, warn, luck, baleful)
6
alarming(adjective, fear, exciting, foreboding)
6
augural(adjective, awful, fear, black, exciting)
6
awesome(adjective, feature, impression, awe)
6
awful(adjective, fear)
6
considerable(adjective, importance, main, extremely significant)
6
extraordinary(adjective, exciting, foreboding)
6
forewarning
6
major(adjective, momentous)
6
miraculous
6
overblown
6
premonitory(adjective, exciting, foreboding, threatening, prediction)
6
stupendous
6
unfavourable
6
unpropitious
6
wondrous(adjective, extraordinary)
5
apocalyptic(adjective, exciting, foreboding, warn, luck)
5
astonishing
5
bodeful(adjective, awful, fear, black, horror)
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APASmart Define. (2015). portentous thesaurus. Retrieved September 28, 2026, from https://smartdefine.org/portentous/thesaurus/synonyms
ChicagoSmart Define. 2015. "portentous thesaurus" https://smartdefine.org/portentous/thesaurus/synonyms (accessed September 28, 2026).
HarvardSmart Define 2015, portentous thesaurus, Smart Define, viewed 28 September, 2026, <https://smartdefine.org/portentous/thesaurus/synonyms>.
MLASmart Define. "portentous thesaurus" 10 April 2015. Web. 28 September 2026. <https://smartdefine.org/portentous/thesaurus/synonyms>