WordWeb Online

1. The quality of being hard to endure, uninviting or formidable
   "the rigor of northern winters";
   - asperity, grimness, hardship, rigour [Brit, Cdn], severity, severeness, rigorousness, rigourousness [Brit, non-standard]
    
2. The quality of being valid and rigorous
   - cogency, validity, rigour [Brit, Cdn]
    
3. Excessive sternness
   "the rigors of boot camp";
   - severity, severeness, harshness, rigour [Brit, Cdn], rigorousness, rigourousness [Brit, non-standard], inclemency, hardness, stiffness

Sounds like: rigor

Derived forms: rigors

Type of: believability, credibility, credibleness, difficultness, difficulty, sternness, strictness

Encyclopedia: Rigor