definition of
rigor

[1] #1 rigor n. [asperity, grimness, hardship, rigour, severity, severeness, rigorousness, rigourousness] something hard to endure; "the asperity of northern winters". wn

[2] #2 rigor n. [cogency, validity, rigour] the quality of being valid and rigorous. wn

[3] #3 rigor n. [severity, severeness, harshness, rigour, rigorousness, rigourousness, inclemency, hardness, stiffness] excessive sternness; "severity of character"; "the harshness of his punishment was inhuman"; "the rigors of boot camp". wn