c.1400, past participle of Middle English gilden, from Old English gyldan (see gild). Also used as a noun with a sense of "gilding" (early 15c.).
Old English gyldan "to gild, to cover with a thin layer of gold," from Proto-Germanic *gulthianan (cf. Old Norse gylla "to gild," Old High German ubergulden "to cover with gold"), from *gulthan "gold" (see gold). Related: Gilded; gilding. Figuratively from 1590s.