| incompliant(adjective, determined, resolute, uncompromising, unshakeable) |
| indurate(adjective, determined, resolute, uncompromising, unshakeable) |
| iron(adjective, determined, resolute, uncompromising, unshakeable) |
| iron-fisted(adjective, tough, severe, firm, harsh) |
| iron-willed(adjective, determined, resolute, uncompromising, unshakeable) |
| lock |
| no-nonsense(adjective, tough, severe, firm, harsh) |
| oppressive(adjective, tough, severe, firm, harsh) |
| picky(adjective, tough, severe, firm, harsh) |
| prudish(adjective, tough, severe, firm, harsh) |
| punctilious(adjective, tough, severe, firm, harsh) |
| puritanical(adjective, tough, severe, firm, harsh) |
| relentless(adjective, determined, resolute, uncompromising, unshakeable) |
| remorseless(adjective, determined, resolute, uncompromising, unshakeable) |
| resolved(adjective, determined, resolute, uncompromising, unshakeable) |
| rigorous(adjective, tough, severe, firm, harsh) |
| rock-ribbed(adjective, determined, resolute, uncompromising, unshakeable) |
| set(adjective, tough, severe, firm, harsh) |
| severe(tough, firm, harsh, stiff, inflexible) |
| square(adjective, tough, severe, firm, harsh) |