rigour -
Character of being unyielding or inflexible.
rigour -
Shrewd questioning.
rigour -
Higher level of difficulty.
Wikipedia
Rigour or 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.