the word 'starchy' is a straightforward english formation. its first element, 'starch', originates from the middle english verb sterchen, meaning 'to stiffen', which is related to old english stearc ('stiff, rigid'). this verb evolved to denote the stiffening substance used on fabrics, and later the carbohydrate. the adjectival suffix '-y', of old english origin, is used to mean 'full of' or 'characterized by'. therefore, the literal meaning 'full of starch' logically extended to describe both the physical quality of containing starch and the metaphorical stiffness of formal, unyielding behavior.

Structure: starch (starch) + y (adjective suffix) starch (from middle english sterche, meaning 'to stiffen', of germanic origin); y (old english adjective-forming suffix, from proto-germanic -igaz)