いっしん 一心 Common word JLPT N1 LinksSentence search for 一心Sentence search for いっしんKanji details for 一 and 心Edit in JMdict Adverb (fukushi), Noun1. one mindAdverb (fukushi), Noun2. wholeheartedness; one's whole heartSee also 一心に Discussions Log in to talk about this word.