noun
Refers to one's innate mental character, temperament, or psychological makeup. Often used in philosophical, psychological, or literary contexts.
彼の心性はとても穏やかだ。
His disposition is very gentle.
この作品には作者の心性がよく表れている。
This work clearly reflects the author's nature.
Compound of 心 (heart, mind) and 性 (nature, character). The exact historical derivation is uncertain, but the word has been used in literary and philosophical Japanese to denote one's inner nature.