one at a time놈 is a rough, derogatory word for a person, often translated as “guy,” “bastard,” or “son of a bitch” depending on context. 한 놈씩 means “one guy at a time.”
KO: 놈씩 상대하면 충분히 이길 수 있어.
EN: You can beat them easily if you take them on one at a time.