出典:Wiktionary
From Middle English selfe-willed, selwillyd, equivalent to self- + willed. Compare Middle English onwille, anewil (“selfwilled, stubborn”), from 古期英語 ānwille (字義どおりに “one-willed, one's own-willed, self-willed”).
self-willed (comparative more self-willed, superlative most self-willed)