104 entries under difficult topic. ×

5
stiff(adjective, great, tough, severe)
5
ticklish(adjective, bad, hard, tough)
5
tricky(adjective, hard, tough, complex)
5
troublesome(adjective, hard, tough, severe, evil)
4
hairy(adjective, bad, severe, rough)
4
sticky(adjective, tough, rough, heavy)
3
complicated(adjective, hard, tough, severe, rough)
3
grave(adjective, tough, severe, unpleasant)
3
mean(adjective, bad, severe, rough, nasty)
3
murder(adjective, hard, tough, severe, rough)
3
oppressive(adjective, heavy)
3
overpowering(adjective, powerful, overwhelming)
3
painful(adjective, hard, tough, severe)
3
puissant(adjective, tough, overwhelming, prevailing)
3
rigorous(adjective, hard, tough, severe, rough)
3
taxing(adjective, hard, tough, severe, rough)
3
wearing(adjective, tough, rough, heavy)
3
wearisome(adjective, tough, severe, awkward)
3
wearying(adjective, tough, rough, heavy)
2
backbreaking(adjective, hard, tough, severe, rough)
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APASmart Define. (2015). formidable thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/formidable/thesaurus/synonyms
ChicagoSmart Define. 2015. "formidable thesaurus" https://smartdefine.org/formidable/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, formidable thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/formidable/thesaurus/synonyms>.
MLASmart Define. "formidable thesaurus" 17 July 2015. Web. 20 September 2026. <https://smartdefine.org/formidable/thesaurus/synonyms>