ないしん 内心 Common word LinksSentence search for 内心Sentence search for ないしんKanji details for 内 and 心Edit in JMdict Noun, Noun which may take the genitive case particle 'no'1. inner thoughts; real intention; inmost heart; one's mindNoun, Adverb (fukushi)2. at heart; deep down; on the insideNoun3. inner center (centre)Mathematics, See also 外心 がいしん Discussions Log in to talk about this word.