Other forms: archenemies
An archenemy is a main foe or opponent. Batman's archenemy is the Joker, and Peter Pan's is Captain Hook.
An archenemy is a hostile adversary. If you're fiercely competitive with your main pickleball rival, you may think of her as your archenemy — even though she's probably a perfectly nice person. Classic archenemies include the evil Cruella deVille, archenemy to the 101 dalmatians, and opposing military generals who vow to defeat each other's armies. The word is derived from the Greek prefix arkh-, "chief," and Latin inimicus, "not friend."