convert; person who has reformed
Refers to someone who has undergone a change of heart, especially in a religious or moral sense. Often used in contexts of repentance or conversion.
He gave his testimony at church as a convert.
The former criminal became a reformed person and spoke about rehabilitation.
Compound of 改心 (reform, change of heart) and 者 (person). The exact historical derivation is uncertain, but the word follows a common pattern for agent nouns.