adversary
US /ˈæd.vɚ.ser.i/
UK /ˈæd.vɚ.ser.i/

1.
Gegner, Widersacher
one's opponent in a contest, conflict, or dispute
:
•
He faced his old adversary in the final round.
Er traf im Finale auf seinen alten Gegner.
•
The two nations have been adversaries for centuries.
Die beiden Nationen waren jahrhundertelang Gegner.