noun
written apology; letter of apology
A formal written statement submitted to acknowledge a mistake or misconduct, often in a workplace or school setting. It explains the circumstances and expresses regret.
遅刻が続いたので、上司に始末書を提出した。
Because I was late repeatedly, I submitted a written apology to my boss.
生徒は廊下を走ったことを始末書に書かされた。
The student was made to write a letter of apology for running in the hallway.
反省文 is a reflective essay focusing on self-examination, commonly used in schools. 始末書 is more formal and often used in professional settings to report an incident.
Compound of 始末 (しまつ, 'management; dealing with a matter') and 書 (しょ, 'document'). Literally a 'document for settling a matter'.