出典:Wiktionary
From Middle English unglad, from 古期英語 unglæd, from Proto-West Germanic *unglad, from Proto-Germanic *ungladaz, equivalent to un- + glad. Cognate with Saterland Frisian uunglääd, West Frisian ûnglêd, Dutch onglad, German Low German ungladd, German unglatt, Danish uglad, Swedish oglad, Icelandic óglaður.