8 letters · 9 points in Scrabble
adjective rigidly accurate; allowing no deviation from a standard
adjective demanding strict attention to rules and procedures
originInherited from Middle English rigorous, from Middle French and Anglo-Norman rigoreus, derived from Late Latin rigōrōsus (stiff, rigid; inflexible). By surface analysis, rigor + -ous.
Etymology from Wiktionary, CC BY-SA 3.0