104 entries under tough topic. ×

60
mighty(adjective, feature, characteristic, strong)
52
terrific(adjective, feature, characteristic, bad, great)
43
heavy(adjective, feature, characteristic, severe)
40
colossal(adjective, feature, characteristic, great)
39
herculean(adjective, feature, characteristic, severe)
38
immense(adjective, feature, characteristic, great)
34
powerful(adjective, strong, difficult, overwhelming)
20
awesome(adjective, great, difficult, wonderful)
18
frightful(adjective, great, terrible, fear)
13
onerous(adjective, severe, difficulty, difficult)
13
arduous(adjective, severe, difficulty, rough)
12
redoubtable(adjective, awful, terrible, fear)
12
impressive(adjective, difficult, awful, wonderful)
12
appalling(adjective, bad, great, fear)
12
laborious(adjective, severe, difficulty, rough)
11
difficult(adjective, hard, severe, evil)
11
dire(adjective, awful, fear, horrible)
10
hard(adjective, severe, evil, difficulty)
10
awful(adjective, great, terrible, fear)
10
burdensome(adjective, severe, difficult, heavy)
11 years ago|23k views|share |citing 
APASmart Define. (2015). formidable thesaurus. Retrieved September 23, 2026, from https://smartdefine.org/formidable/thesaurus/synonyms
ChicagoSmart Define. 2015. "formidable thesaurus" https://smartdefine.org/formidable/thesaurus/synonyms (accessed September 23, 2026).
HarvardSmart Define 2015, formidable thesaurus, Smart Define, viewed 23 September, 2026, <https://smartdefine.org/formidable/thesaurus/synonyms>.
MLASmart Define. "formidable thesaurus" 17 July 2015. Web. 23 September 2026. <https://smartdefine.org/formidable/thesaurus/synonyms>