141 entries under tough topic. ×

1
tenacious(adjective, strong, hard, sound)
1
thick-skinned(adjective, calm, hard, cool)
1
unbending(adjective, strong, hard, fixed)
1
uncompromising(adjective, firm, fixed, distant)
1
unfeeling(adjective, hard, rough, harsh)
1
unflexible(adjective, firm, stiff, distant)
1
unkind(adjective, hard, harsh, indifferent)
1
unrelenting(adjective, firm, harsh, cruel)
1
unswayable(adjective, firm, fixed, distant)
1
unyielding(adjective, strong, hard, sound)
1
uptight(adjective, firm, fixed, distant)
1
well-built(adjective, strong, sound, solid)
1
well-founded(adjective, strong, sound, solid)
1
well-made(adjective, strong, sound, solid)
0
acrimonious(adjective, severe, harsh, cruel)
0
adamant(adjective, strong, hard, fixed)
0
adamantine(adjective, set, strong, hard)
0
antagonistic(adjective, severe, harsh, cruel)
0
austere(adjective, harsh, cruel, grim)
0
bitter(adjective, harsh, cruel, grim)
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APASmart Define. (2015). hard as nails thesaurus. Retrieved September 30, 2026, from https://smartdefine.org/hard_as_nails/thesaurus/synonyms
ChicagoSmart Define. 2015. "hard as nails thesaurus" https://smartdefine.org/hard_as_nails/thesaurus/synonyms (accessed September 30, 2026).
HarvardSmart Define 2015, hard as nails thesaurus, Smart Define, viewed 30 September, 2026, <https://smartdefine.org/hard_as_nails/thesaurus/synonyms>.
MLASmart Define. "hard as nails thesaurus" 10 April 2015. Web. 30 September 2026. <https://smartdefine.org/hard_as_nails/thesaurus/synonyms>