76 entries under tough topic. ×

18
difficult(adjective, hard, great, awkward)
10
formidable(adjective, severe, difficult, awkward)
9
serious(adjective, hard, difficult, importance)
8
severe(adjective, hard, difficult, awkward)
6
demanding(adjective, hard, severe, difficult)
5
arduous(adjective, hard, great, severe)
4
exhausting(adjective, hard, difficult, awkward)
4
laborious(adjective, great, severe, difficult)
4
stiff(severe, painful, demanding, problematic)
3
hard(adjective, great, difficult, awkward)
3
rough(adjective, great, difficult, terrible)
3
trying(adjective, hard, severe, difficult)
2
burdensome(adjective, severe, difficult, awkward)
2
effortful(adjective, great, severe, difficult)
2
exacting(adjective, hard, severe, difficult)
2
onerous(adjective, hard, great, severe)
2
strenuous(adjective, great, severe, difficult)
2
titanic(severe, painful, problematic, trying)
2
toilsome(adjective, great, severe, difficult)
2
unyielding(adjective, severe, painful, problematic)
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APASmart Define. (2016). challenging thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/challenging/thesaurus/synonyms
ChicagoSmart Define. 2016. "challenging thesaurus" https://smartdefine.org/challenging/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, challenging thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/challenging/thesaurus/synonyms>.
MLASmart Define. "challenging thesaurus" 2 March 2016. Web. 24 September 2026. <https://smartdefine.org/challenging/thesaurus/synonyms>