| adjective | rigidly accurate; allowing no deviation from a standard “rigorous application of the law” |
| adjective | (of rules) stringently enforced “hard-and-fast rules” |
| adjective | characterized by strictness, severity, or restraint |
| adjective | incapable of compromise or flexibility |
| adjective | severe and unremitting in making demands “an exacting instructor” |
| rigorousness | noun | excessive sternness |
| rigor | noun | the quality of being valid and rigorous |
| strictness | noun | conscientious attention to rules and details |
| nonindulgence | noun | the trait of great self-denial (especially refraining from worldly pleasures) |
| rigidness | noun | the quality of being rigid and rigorously severe |
| rigidity | noun | the quality of being rigid and rigorously severe |
| sternness | noun | uncompromising resolution |