noun (n)

• something hard to endure(noun.attribute)

  Synonym:
  asperity, grimness, hardship, rigorousness, rigour, rigourousness, severeness, severity
  

  source: wordnet30
• the quality of being valid and rigorous(noun.attribute)

  Synonym:
  cogency, rigour, validity
  

  source: wordnet30
• excessive sternness(noun.attribute)

  Example:
  The rigors of boot camp.
  

  Synonym:
  hardness, harshness, inclemency, rigorousness, rigour, rigourousness, severeness, severity, stiffness
  

  source: wordnet30
• Rigidity; stiffness.(noun)

  source: webster1913
• The becoming stiff or rigid; the state of being rigid; rigidity; stiffness; hardness.(noun)

  source: webster1913