an enemy / an opponent, a competitor / (historical) the other party in a lawsuit / 的: (historical) in the red-light district, a term of reference used between prostitutes and customers

an enemy / revenge, vengeance / opponent (of the game or conflict) / (archaic, obsolete) marriage partner

的: (historical) (by extension from the red-light district usage) term of third-person reference: that guy, that one

enemy / foe

to rival

(informal) the United Nations

(medicine) adhesion / a collusive relationship, collusion

(medicine) to adhere / to have a collusive relationship

lacking a clear attitude or action; hesitantly

technique