100 entries under hard topic. ×

36
fusty(adjective, warm, difficult, rank)
26
flat(adjective, dull, set, weak)
25
musty(adjective, dull, set, strong)
24
hackneyed(adjective, dull, set, mean, beat)
24
nasty(adjective, difficult, rank, complex)
22
trite(adjective, dull, set, mean)
22
old(adjective, beat, last, dead)
21
banal(adjective, dull, set, weak)
21
commonplace(adjective, dull, set, simple)
21
oppressive(adjective, warm, difficult, complex)
21
sluggish(adjective, difficult, complex)
21
tired(adjective, dull, set, beat)
20
dull(adjective, set, weak, simple)
19
insipid(adjective, dull, weak, flat)
18
heavy-handed(adjective, dull, difficult, complex)
18
ponderous(adjective, dull, difficult, complex)
18
sticky(adjective, difficult, complex, tight)
17
dry(verb, adjective, take, dull)
17
stereotyped(adjective, dull, set, flat)
15
dead(adjective, dull, quiet, weak)
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APASmart Define. (2015). stale thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/stale/thesaurus/synonyms
ChicagoSmart Define. 2015. "stale thesaurus" https://smartdefine.org/stale/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2015, stale thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/stale/thesaurus/synonyms>.
MLASmart Define. "stale thesaurus" 10 April 2015. Web. 24 September 2026. <https://smartdefine.org/stale/thesaurus/synonyms>