RIGOUR
severity, severeness, harshness, rigor, rigour, rigorousness, rigourousness, inclemency, hardness, stiffness
(noun) excessive sternness; “severity of character”; “the harshness of his punishment was inhuman”; “the rigors of boot camp”
asperity, grimness, hardship, rigor, rigour, severity, severeness, rigorousness, rigourousness
(noun) something hard to endure; “the asperity of northern winters”
cogency, validity, rigor, rigour
(noun) the quality of being valid and rigorous
Source: WordNet® 3.1
Etymology
Noun
rigour (countable and uncountable, plural rigours)
Severity or strictness.
Harshness, as of climate.
A trembling or shivering response.
Character of being unyielding or inflexible.
Shrewd questioning.
Higher level of difficulty.
(British) Misspelling of rigor.
Source: Wiktionary