| unyielding(adjective, strong, hard, tough, firm) |
| uncompromising(adjective, severe, firm, harsh, stubborn) |
| rigid(adjective, strong, hard, tough, severe) |
| badass(noun, adjective, person, hector) |
| faithful(adjective, close, correct, firm, honest) |
| inflexible(adjective, strong, hard, tough, severe) |
| intransigent(adjective, dedicated) |
| obstinate(adjective, firm, determined, resolute, impulsive) |
| stern(adjective, severe, firm, harsh, serious) |
| stiff(firm, stubborn, unyielding, unbending) |
| hard(adjective, strong, tough, severe, firm) |
| hardcore |
| determined(adjective, firm, resolute, impulsive, stubborn) |
| devoted(adjective, close, correct, firm, honest) |
| die-hard(adjective, firm, honest, upright, sure) |
| explicit(adjective, dedicated) |
| inveterate(adjective, established) |
| resolute(adjective, close, correct, firm, honest) |
| staunch(adjective, close, correct, firm, honest) |
| steadfast(adjective, close, correct, firm, honest) |