This four-character idiom literally breaks down as 'repeatedly (屡) taught (教), yet not (不) reformed (改)'. It describes a person who continues to commit the same mistake or misconduct despite repeated warnings, instruction, or correction. The emphasis is on stubbornness and refusal to change—even after multiple opportunities to improve. It carries a strong negative connotation and is often used in formal, evaluative, or disciplinary contexts.

The term frequently appears in education, law enforcement, workplace evaluations, or family discipline scenarios. While it can refer to any persistent wrongdoing, it’s especially common when describing habitual offenders, chronically disobedient students, or employees who ignore feedback. Grammatically, it functions as a predicate adjective—typically following subjects like '他' or '这人'—and rarely stands alone without context.