Rigorous

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.

Severe; intense; inclement; as, a rigorous winter.

Violent.

demanding strict attention to rules and procedures; "rigorous discipline"; "tight security"; "stringent safety measures"