From 牛頭 (Gozu, “Ox-Head”) + 馬頭 (Mezu, “Horse-Head”). Compare Chinese 牛頭馬面/牛头马面 (niútóumǎmiàn, literally “Ox-Head and Horse-Face”).
牛(ご)頭(ず)馬(め)頭(ず) • (Gozu Mezu) ←ごづめづ (godumedu)?