rigor

rig·or  (rgr)

n.

1. Strictness or severity, as in temperament, action, or judgment.

2. A harsh or trying circumstance; hardship. See Synonyms at difficulty.

3. A harsh or cruel act.

4. Medicine Shivering or trembling, as caused by a chill.

5. Physiology A state of rigidity in living tissues or organs that prevents response to stimuli.

6. Obsolete Stiffness or rigidity.

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[Middle English rigour, from Old French, from Latin rigor, from rigre, to be stiff; see reig- in Indo-European roots.]

Thesaurus

Noun	1.	rigor - something hard to endure; "the asperity of northern winters" asperity, rigorousness, rigourousness, severeness, severity, rigour, grimness, hardship difficultness, difficulty - the quality of being difficult; "they agreed about the difficulty of the climb" sternness - the quality (as of scenery) being grim and gloomy and forbidding; "the sternness of his surroundings made him uncomfortable"
	2.	rigor - the quality of being valid and rigorous rigour, validity, cogency believability, credibility, credibleness - the quality of being believable or trustworthy
	3.	rigor - excessive sternness; "severity of character"; "the harshness of his punishment was inhuman"; "the rigors of boot camp" inclemency, rigorousness, rigourousness, rigour, harshness, severeness, severity, stiffness, hardness sternness, strictness - uncompromising resolution