crusty

the word 'crusty' is a native english formation, built upon the noun 'crust', which entered middle english from old french 'cruste', itself derived from latin 'crusta' meaning a hard surface, shell, or rind. the latin term is of uncertain origin but may be related to proto-indo-european roots for something frozen or hardened. the adjectival suffix '-y', of old english/germanic origin, is added to indicate the possession of qualities. thus, the literal meaning "having a crust" evolved metaphorically to describe a person with a hard, irritable exterior, much like a hardened piece of bread.

Structure: crust (hard outer layer) + y (adjective-forming suffix) crust (from latin 'crusta', meaning hard shell, rind, or surface layer); y (from old english '-ig', a suffix forming adjectives meaning "characterized by, full of, having the quality of").