127 entries under tough topic. ×

1
labored(adjective, hard, severe, rough)
1
lifeless(adjective, rational, straightforward, sober)
1
mean(adjective, rough, difficult, unpleasant)
1
merciless(adjective, severe, rough, difficult)
1
mortified(adjective, strong, hard, severe)
1
mulish(adjective, strong, hard, severe)
1
mundane(adjective, rational, straightforward, sober)
1
naked(adjective, rational, straightforward, sober)
1
obdurate(adjective, close, strong, hard)
1
objective(adjective, rational, straightforward, sober)
1
phlegmatic(adjective, rational, straightforward, sober)
1
plain(adjective, calm, open, honest)
1
pragmatic(adjective, rational, straightforward, sober)
1
prosaic(adjective, rational, straightforward, sober)
1
prosy(adjective, rational, straightforward, sober)
1
scabrous(adjective, rough, difficult, heavy)
1
slavish(adjective, rough, difficult, heavy)
1
stiff-necked(adjective, strong, hard, severe)
1
stoic(adjective, rational, straightforward, sober)
1
sturdy(adjective, strong, hard, solid)
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APASmart Define. (2016). serious thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/serious/thesaurus/synonyms
ChicagoSmart Define. 2016. "serious thesaurus" https://smartdefine.org/serious/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2016, serious thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/serious/thesaurus/synonyms>.
MLASmart Define. "serious thesaurus" 24 February 2016. Web. 30 September 2026. <https://smartdefine.org/serious/thesaurus/synonyms>