noun
previous visitor; earlier guest; person already there
Refers to someone who arrived or is present before the speaker, often in contexts like shops, restaurants, or appointments.
店に入ると、先客が一人いた。
When I entered the shop, there was one customer already there.
予約の時間より早く着いたが、先客が待っていた。
I arrived earlier than the reservation time, but a previous visitor was already waiting.