せいしつ性質seishitsu
1.
The observable expression of an individual's will and emotions, often revealed through their behavior and attitudes.
2.
The inherent characteristics or special features that define and distinguish an object or substance, particularly those that manifest in its performance or behavior under various conditions.
3.
The innate qualities or temperament that someone is born with, shaping their personality and nature.
Example:
彼は性質が頑固だ。