[adj] demanding strict attention to rules and procedures; "rigorous discipline"; "tight security"; "stringent safety measures"
[adj] rigidly accurate; allowing no deviation from a standard; "rigorous application of the law"; "a strict vegetarian"
[adj] (of circumstances; especially weather) causing suffering; "brutal weather"; "northern winters can be cruel"; "a cruel world"; "a harsh climate"; "a rigorous climate"; "unkind winters"