the term "square-jawed" is a modern english compound adjective formed from two distinct elements. the first part, "square," originates from latin via old french, carrying its geometric sense of a right-angled shape. the second part, "jawed," derives from a middle english noun of uncertain, possibly french, origin, combined with the common english adjectival suffix '-ed'. the compound logically combines these elements to describe a physical feature—a jaw with a broad, angular outline reminiscent of a square's shape. this literal description has evolved into a conventional descriptor for a facial feature associated with stereotypical masculinity, strength, and resoluteness.

Structure: square (shape) + jawed (having a jaw) - square: from old french 'esquare', from latin 'exquadra', meaning "to square". in this compound, it functions as an adjective describing the shape of the jaw. - jawed: from middle english 'jawe', of uncertain origin, possibly from old french 'joue' meaning "cheek". the suffix '-ed' is added to the noun 'jaw' to form an adjective meaning "having a jaw (of a specified kind)".