the word 'stout' entered middle english from the old french 'estout', meaning brave or proud. this old french term is itself believed to have germanic origins, likely from a west germanic root related to concepts of pride, boldness, and possibly swelling or puffing up. the semantic journey from "bold, proud" to its modern meanings is logical: a bold person is mentally strong (leading to "brave and determined"), and the physical connotations of being puffed up with pride or boldness likely influenced the later development of meanings related to physical thickness, strength, and heaviness of build.

the word is a simplex form derived from old french 'estout', meaning "bold, proud". it is not productively formed from separable morphemes in modern english.