14
simple(adjective, ability, slow, plain, pure)
14
somber(adjective, upset, quiet, severe, sad)
14
unexciting(adjective, weak, plain, mild, stupid)
14
vague(adjective, weak, soft, gentle, obscure)
14
weak(adjective, hard, light, simple, soft)
13
backward(adjective, simple, ability, low, slow)
13
feeble(adjective, weak, soft, gentle, incompetence)
13
gray(noun, adjective, light, soft, poor)
13
hazy(adjective, quiet, weak, soft, gentle)
13
indolent(adjective, slow, careless, relaxed, indifferent)
13
insensible(adjective, quiet, flat, attitude, slow)
13
irksome(adjective, simple, excite, plain, stupid)
13
moronic(adjective, simple, slow, silly, foolish)
13
muffle(verb, calm, quiet, reduce, diminish)
13
muted(adjective, quiet, weak, simple, soft)
13
opaque(adjective, obscure, flat, slow, dark)
13
reduce(verb, stop, upset, quiet, check)
13
routine(noun, adjective, set, weak, simple)
13
sleepy(adjective, low, careless, relaxed, indifferent)
13
sober(adjective, characteristic, quiet, tough, severe)
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APASmart Define. (2016). dull thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/dull/thesaurus/synonyms
ChicagoSmart Define. 2016. "dull thesaurus" https://smartdefine.org/dull/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, dull thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/dull/thesaurus/synonyms>.
MLASmart Define. "dull thesaurus" 29 March 2016. Web. 24 September 2026. <https://smartdefine.org/dull/thesaurus/synonyms>