As a boy's name this is a pet form of Jeremy or Gerald, or occasionally of Gerard and Jerome. As a girl's name it is a variant spelling of Gerry, and is sometimes bestowed as an independent given name, as in the case of the American model and actress Jerry Hall (b. 1956).
English: nickname from Middle English fein, fayn, fane ‘glad’, ‘well disposed’ (Old English fægen). The word seems also to have been occasionally used as a personal name in the Middle Ages, from which the surname may derive in some instances.