「失礼します」 literally means "I am going to commit a rudeness." It is a very common polite phrase used when entering a room (like a teacher's office), hanging up the phone, or walking past someone in a tight space. It serves as "Excuse me" or "Goodbye" in formal settings.

入室する時、退出する時、電話を切る時などに使う礼儀正しい表現です。「礼儀を欠いた行動をします」と事前に断ることで、相手への敬意を示します。