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

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

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

(used after an adjective in the te-form) unbearable / unable to lose to; no match for

to rival

enemy / foe

a cat

cat

use one thing for many purposes / work someone hard

to use one's head