The compound adjective 'wild-haired' is a relatively modern English formation, built from native Germanic elements. The first element, 'wild', descends from the Proto-Germanic wilthijaz, carrying the core sense of being in a natural, untamed state. The second element, 'hair', originates from Proto-Germanic khæran. The suffix '-ed' is added to the noun 'hair' to create the participial adjective form, a productive pattern in English (e.g., 'blue-eyed', 'long-legged'). The literal construction "having hair that is wild" logically evolved to describe both a physically disheveled appearance and, by metaphorical extension, an eccentric or unrestrained personality.

Structure: wild (untamed) + hair (filamentous growth) + ed (adjective suffix) - wild: From Old English wilde (in a natural state, untamed, uncultivated). Functional role: Descriptive base. - hair: From Old English hær (hair of the head, a hair). Functional role: Noun root specifying the object of description. - ed: From Old English -ede, an adjectival suffix used to form adjectives from nouns, meaning "having, provided with, characterized by".