Manifesting, exercising, or favoring rigor; allowing no abatement or mitigation; scrupulously accurate; exact; strict; severe; relentless; as, a rigorous officer of justice; a rigorous execution of law; a rigorous definition or demonstration.
used of circumstances (especially weather) that cause suffering; "brutal weather"; "northern winters can be cruel"; "a cruel world"; "a harsh climate"; "a rigorous climate"; "unkind winters"