87 entries under rigid topic. ×

11
tough(adjective, strong, hard, severe, rough)
10
tight(adjective, severe, careful, strict)
9
oppressive(adjective, hard, tough, severe, rough)
9
painstaking(adjective, harsh, honorable, reliable)
8
rough(adjective, strong, hard, tough, severe)
8
unbending(adjective, strong, hard, tough, severe)
7
critical(adjective, severe, harsh, precise)
7
dour(adjective, tough, severe, firm, harsh)
7
finicky(adjective, harsh, thoughtful, precise, sober)
7
firm(noun, adjective, strong, hard, complete)
7
obstinate(adjective, hard, severe, resolute)
6
adamant(adjective, strong, hard, tough, harsh)
6
burdensome(adjective, hard, severe, rough, difficult)
6
fussy(adjective, harsh, thoughtful, sober)
6
onerous(adjective, hard, severe, rough, difficult)
6
unrelenting(adjective, strong, hard, tough, severe)
5
Draconian(adjective, tough, severe, firm, harsh)
5
immovable(adjective, set, strong, hard, tough)
5
puritanical(adjective, tough, severe, firm, harsh)
5
unchangeable(adjective, hard, resolute, inflexible)
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APASmart Define. (2016). rigorous thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/rigorous/thesaurus/synonyms
ChicagoSmart Define. 2016. "rigorous thesaurus" https://smartdefine.org/rigorous/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2016, rigorous thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/rigorous/thesaurus/synonyms>.
MLASmart Define. "rigorous thesaurus" 26 February 2016. Web. 23 September 2026. <https://smartdefine.org/rigorous/thesaurus/synonyms>