- 1a (1) : harsh inflexibility in opinion, temper, or judgment : severity (2) : the quality of being unyielding or inflexible : strictness (3) : severity of life : austerity
- b : an act or instance of strictness, severity, or cruelty
- 2: a tremor caused by a chill
- 3: a condition that makes life difficult, challenging, or uncomfortable; especially : extremity of cold
- 4: strict precision : exactness <logical rigor>
- 5a obsolete : rigidity, stiffness
Rigor has a number of meanings in relation to intellectual life and discourse. These are separate from public and political applications with their suggestion of laws enforced to the letter, or political absolutism. A religion, too, may be worn lightly, or applied with rigour.
An attempted short definition of intellectual rigour might be that no suspicion of double standard be allowed: uniform principles should be applied. This is a test of consistency, over cases, and to individuals or institutions (including the speaker, the speaker's country and so on). Consistency can be at odds here with a forgiving attitude, adaptability, and the need to take precedent with a pinch of salt. If a topic or case is dealt with in a rigorous way, it means that it is dealt with in a comprehensive, thorough and complete way, leaving no room for inconsistencies.
"The rigour of the game" is a quotation from Charles Lamb about whist. It implies that the demands of thinking accurately and to the point over a card game can serve also as entertainment or leisure. Intellectual rigour can therefore be sometimes seen as the exercise of a skill. It can also degenerate into pedantry, which is intellectual rigour applied to no particular end, except perhaps self-importance.
Scholarship can be defined as intellectual rigour applied to the quality control of information, which implies an appropriate standard of accuracy, and scepticism applied to accepting anything on trust. It requires close attention to criteria for logical consistency, as well as to all relevant evidence and possible differences of interpretation.