self-control; self-mastery; self-restraint; self-denial
克己心を養うことが武道の基本である。
Cultivating self-control is fundamental to martial arts.
克己復礼という儒教の教えを実践している。
They practice the Confucian teaching of self-restraint and propriety.
困難な状況でも克己の精神を忘れなかった。
Even in difficult situations, they did not forget the spirit of self-mastery.