2
steely(adjective, strong, hard, tough, severe)
2
true-blue(adjective, close, correct, firm, honest)
2
unbending(adjective, strong, hard, tough, firm)
2
ungiving(adjective, firm, unyielding)
2
unrelenting(adjective, strong, hard, tough, severe)
2
warrior(noun, hector)
2
wicked(noun, coarse, vulgar, indecent, naughty)
1
X-rated(adjective, offensive, dirty, coarse, vulgar)
1
affectionate(adjective, close, correct, firm, honest)
1
allegiant(adjective, close, correct, firm, honest)
1
astringent(adjective, strong, hard, tough, severe)
1
attached(adjective, close, correct, firm, honest)
1
austere(adjective, strong, hard, tough, severe)
1
authoritarian(adjective, strong, hard, tough, severe)
1
behind one(expression, adjective, close, correct, firm)
1
bitter(adjective, strong, hard, tough, severe)
1
bullheaded(adjective, strong, hard, tough, severe)
1
by the book(expression, adjective, idiom, strong, hard)
1
cast-iron
1
ceaseless
10 years ago|2.7k views|share |citing 
APASmart Define. (2016). hard-core thesaurus. Retrieved September 22, 2026, from https://smartdefine.org/hard-core/thesaurus/synonyms
ChicagoSmart Define. 2016. "hard-core thesaurus" https://smartdefine.org/hard-core/thesaurus/synonyms (accessed September 22, 2026).
HarvardSmart Define 2016, hard-core thesaurus, Smart Define, viewed 22 September, 2026, <https://smartdefine.org/hard-core/thesaurus/synonyms>.
MLASmart Define. "hard-core thesaurus" 28 March 2016. Web. 22 September 2026. <https://smartdefine.org/hard-core/thesaurus/synonyms>