Refers to a competitor or adversary, often in a confrontational or competitive context. Slightly formal or literary.
彼は長年の敵手に勝利した。
He defeated his longtime rival.
worthy opponent; worthy rival; good match
Compound of 敵 (enemy) and 手 (hand, opponent). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'rival' or 'adversary'.