104 entries under tough topic. ×

10
daunting(adjective, awful, horrible, grand)
10
menacing(adjective, bad, severe, unpleasant)
10
strenuous(adjective, severe, rough, difficult)
9
horrific(adjective, bad, great, fear)
9
imposing(adjective, awful, wonderful, horrible)
9
rough(adjective, hard, nasty, difficult)
9
terrifying(adjective, awful, wonderful, grand)
8
horrible(adjective, great, unpleasant, awful)
8
severe(adjective, appearance, great, difficult)
8
toilsome(adjective, severe, difficulty, difficult)
8
uphill(adjective, severe, rough, difficult)
7
demanding(adjective, severe, rough, difficult)
7
effortful(adjective, severe, difficult, heavy)
7
fierce(adjective, great, heavy, horrible)
7
great(adjective, difficult, big, large)
7
overwhelming(adjective, great, awful, grand)
6
challenging(adjective, severe, difficult, awkward)
6
dangerous(adjective, hard, severe, evil)
6
operose(adjective, severe, difficulty, rough)
6
threatening(adjective, severe, unpleasant, important)
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APASmart Define. (2015). formidable thesaurus. Retrieved September 25, 2026, from https://smartdefine.org/formidable/thesaurus/synonyms
ChicagoSmart Define. 2015. "formidable thesaurus" https://smartdefine.org/formidable/thesaurus/synonyms (accessed September 25, 2026).
HarvardSmart Define 2015, formidable thesaurus, Smart Define, viewed 25 September, 2026, <https://smartdefine.org/formidable/thesaurus/synonyms>.
MLASmart Define. "formidable thesaurus" 17 July 2015. Web. 25 September 2026. <https://smartdefine.org/formidable/thesaurus/synonyms>