Refers to one's innate mental character, temperament, or psychological makeup. Often used in philosophical, psychological, or literary contexts.
His disposition is very gentle.
This work clearly reflects the author's nature.
egocentrism; self-centeredness
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.