本性 "original nature," or "inherent nature" (prakṛti). An originally present fundamental quality of something, often equivalent to the concept of "self-nature" (自性 - Skt. svabhāva; Pali sabhāva). Buddhism, and especially Mahāyāna, generally rejects the concept of an inherent nature as being a mistaken perception. But on the other hand, in accordance with the general Chinese philosophical perception of the human nature as being originally good, certain texts will allude to the mind's inherent purity or quiescence.

The spirit one possesses by nature; hence, the Buddha-nature; the Buddha-nature within; one's own nature.

A Dictionary of Chinese Buddhist Terms, William Edward Soothill and Lewis Hodous

指固有之性德。即常住不變之絕對真實性。圓覺經（大一七‧九一九中）：「若此覺心本性清淨，因何染污？」

佛光電子大辭典

p1962

【梵】tattvam
【滿】da banin
【蒙】terekhü chinar
【漢】本性

南山律學辭典 - Nanshan Vinaya Dictionary

本性佛===（術語）華嚴十種佛之一。佛具大智慧照了一切法，自性本來是佛，故名本性佛。

丁福保《佛學大辭典》