4
milky(adjective, white, cloudy)
4
mysterious
4
mystifying(adjective, unfathomable, impenetrable, unintelligible, puzzling)
4
nubilous(adjective, hard, gloomy, gray, dense)
4
obscured(adjective, dull, dark, gloomy, faint)
4
recondite
4
shapeless(adjective, obscure)
4
slow
4
sooty(adjective, dull, soft, obscure, flat)
4
stolid(adjective, dull, insensitive, simple-minded, dull-witted)
4
stupid
4
thickheaded
3
dumb(adjective, dull, silly, foolish, stupid)
3
amphibological(adjective, hard)
3
aphotic(adjective, dull, dark, gloomy, dim)
3
backward
3
caliginous(adjective, dull, dark, gloomy, dim)
3
clear as mud(expression, idiom, unfathomable, impenetrable, unintelligible)
3
cloddish
3
close(adjective, set, solid, heavy, deep)
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APASmart Define. (2016). opaque thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/opaque/thesaurus/synonyms
ChicagoSmart Define. 2016. "opaque thesaurus" https://smartdefine.org/opaque/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, opaque thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/opaque/thesaurus/synonyms>.
MLASmart Define. "opaque thesaurus" 29 February 2016. Web. 22 September 2026. <https://smartdefine.org/opaque/thesaurus/synonyms>