약속이 있어서

because I have plans

→ 약속

phrase Uncommon #14,594

because I have plans 약속 can mean plans, an appointment, or an engagement, depending on context.

KO: 오늘은 약속이 있어서 못 가요.

EN: I can't go today because I have plans.

Because I have plans.

— 라라랜드 (2016)