75 entries under demanding topic. ×

8
rough(adjective, strong, hard, tough, severe)
8
rugged(adjective, strong, hard, tough, severe)
7
brutal(adjective, hard, tough, severe, rough)
7
laborious(adjective, hard, tough, severe, rough)
6
burdensome(adjective, hard, severe, rough, difficult)
6
onerous(adjective, hard, severe, rough, difficult)
5
unsparing(adjective, strong, hard, tough, severe)
4
challenging(adjective, difficult, awkward, thorough)
4
exhausting(adjective, hard, tough, severe, rough)
4
intemperate(adjective, hard, tough, severe, rough)
4
strenuous(adjective, hard, tough, severe, rough)
3
effortful(adjective, tough, rough, difficult, harsh)
3
formidable(adjective, hard, tough, severe, rough)
3
heavy(adjective, strong, hard, tough, severe)
3
intricate(adjective, tough, rough, difficult, heavy)
3
mean(adjective, tough, severe, rough, difficult)
3
toilsome(adjective, hard, tough, severe, rough)
3
uphill(adjective, hard, tough, severe, rough)
2
difficile(adjective, tough, rough, difficult, heavy)
2
grinding(adjective, tough, severe, rough, difficult)
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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>