171 entries under tough topic. ×

50
strict(adjective, feature, strong, hard)
41
severe(adjective, strong, hard, correct)
33
rigid(adjective, strong, hard, correct)
32
stringent(adjective, hard, severe, rough)
32
harsh(adjective, strong, hard, severe)
28
stern(adjective, hard, severe, rough)
27
scrupulous(adjective, feature, hard, correct)
25
hard(adjective, strong, severe, rough)
24
exacting(adjective, hard, severe, fine)
21
inflexible(adjective, strong, hard, severe)
21
punctilious(adjective, hard, correct, severe)
19
austere(adjective, strong, hard, severe)
15
unyielding(adjective, strong, hard, severe)
10
obdurate(adjective, strong, hard, severe)
9
bitter(adjective, strong, hard, severe)
9
oppressive(adjective, hard, severe, rough)
8
arduous(adjective, hard, severe, rough)
8
inclement(adjective, hard, severe, rough)
8
relentless(adjective, strong, hard, severe)
8
rough(adjective, strong, hard, severe)
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APASmart Define. (2016). rigorous thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/rigorous/thesaurus/synonyms
ChicagoSmart Define. 2016. "rigorous thesaurus" https://smartdefine.org/rigorous/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2016, rigorous thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/rigorous/thesaurus/synonyms>.
MLASmart Define. "rigorous thesaurus" 26 February 2016. Web. 25 September 2026. <https://smartdefine.org/rigorous/thesaurus/synonyms>