rigor Definition

rigor
noun

1. medicine.
A sense of chilliness accompanied by shivering, a preliminary symptom of many diseases.
2. A rigid irresponsive state caused by a sudden shock.

Etymology: 14c: Latin, meaning ‘numbness' or ‘stiffness'.

---

rigour
rigor
noun

1. Stiffness; hardness.
2. Strictness or severity of temper, behaviour or judgement.

Thesaurus: strictness, rigidity, meticulousness,asperity, austerity, firmness, inflexibility, sternness, harshness; Antonym: leniency, mildness.
3. Strict enforcement of rules or the law.
4. Said of a particular situation or circumstances, eg of weather or climate: harshness or severity.

Form: rigours (usually)
5. Harshness or severity of life; austerity.
6. Strict precision or exactitude, eg of thought.

Etymology: 14c: from Latin rigor stiffness.