1. The quality of being valid and rigorous
   "The rigour of the experiment impressed the scientific community";
   - cogency, validity, rigor [US]
    
2. Excessive or stern strictness in attitude, judgment, or treatment
   "the rigours of boot camp";
   - severity, severeness [rare], harshness, rigor [US], rigorousness, inclemency [archaic], stiffness
    
3. The quality of being hard to endure, uninviting or formidable
   "the rigour of northern winters";
   - asperity, grimness, hardship, rigor [US], severity, severeness [rare], rigorousness

Sounds like: rigger

Derived forms: rigours

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

Encyclopedia: Rigour