rigorous Synonyms

strict severe rigid stern inflexible exact painstaking scrupulous harsh stringent unyielding stiff uncompromising demanding detailed tight exacting thorough meticulous austere careful precise steep religious sedulous reliable ramrod punctual tough spartan restringing sound siberian selective rigorist rugged sharp scholastic scientific punctilious strait gruelling dead set unwavering pinpoint no-nonsense unpermissive hardline on the button right on