Rigor

1. noun

   the quality of being valid and rigorous

   Similar: cogency, validity, rigour

2. noun

   something hard to endure

   “the asperity of northern winters”

   Similar: asperity, grimness, hardship, rigour, severity, severeness

3. noun

   excessive sternness

   “severity of character”

   Similar: severity, severeness, harshness, rigour, rigorousness, rigourousness