彼女は気性が激しく、すぐに怒り出す。
She has a fiery temperament and loses her temper quickly.
父はさっぱりした気性で、細かいことを気にしない。
My father has an easygoing nature and doesn't worry about little things.
この馬は気性が荒いので、乗りこなすのが難しい。
This horse has a wild temperament, so it is hard to ride.