noun
learning from experience; repenting; improving one's nature
Almost exclusively used in the set phrase 性懲りもなく (しょうこりもなく), meaning 'without learning one's lesson' or 'incorrigibly'. The standalone noun is rare.
See also: 性懲りもなく (しょうこりもなく)
彼は性懲りもなくまた同じ失敗を繰り返した。
He repeated the same mistake again without learning his lesson.
性懲りもなくギャンブルに手を出す。
He goes back to gambling, never learning.
懲りる is a common verb meaning 'to learn a lesson from a bad experience'. 性懲り is a rare noun form that appears almost only in the phrase 性懲りもなく.
Compound of 性 (しょう, 'nature, disposition') and 懲り (こり, 'learning from experience', from 懲りる). The exact historical derivation is uncertain, but the word is now fossilized in the adverbial phrase 性懲りもなく.