出典:Wiktionary
From Middle English self-wil, self-wille, from 古期英語 sylfwill, selfwill, selfwille (“self-will”), from Proto-West Germanic *selbawilljō, from Proto-Germanic *selbawiljô (“self-will”), equivalent to self- + will. Cognate with Old High German selbwillo, selpwillo, Old Norse sjalfvili.