8
unintelligent
7
blank
7
cheerless(adjective, unhappy, depressing)
7
harsh(calm, soft, low)
6
night
6
sad(adjective, happy, joy, glad, merry)
5
depressed
5
blue
5
foul
5
leaden
5
pessimistic(adjective, feelings, emotions, optimistic)
5
shadowy(adjective, distinct, hazy)
5
stupid(adjective, sharp, intelligent)
5
sullen(adjective, upset, brooding)
5
threatening
4
boring
4
colorless
4
dumb(adjective, sharp, stupid, unintelligent)
4
glum(adjective, cheerful)
4
hopeless(adjective, pessimistic, futile)
10 years ago|9.8k views|share |citing 
APASmart Define. (2016). bright thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/bright/thesaurus/antonyms
ChicagoSmart Define. 2016. "bright thesaurus" https://smartdefine.org/bright/thesaurus/antonyms (accessed September 23, 2026).
HarvardSmart Define 2016, bright thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/bright/thesaurus/antonyms>.
MLASmart Define. "bright thesaurus" 31 March 2016. Web. 23 September 2026. <https://smartdefine.org/bright/thesaurus/antonyms>