Another word for enemy
A national or public opponent
foe, attacker, antagonist, opponent, adversary, public enemy, criminal, opposition, fifth column, enemy within the gates, borer from within, saboteur, spy, foreign agent, assassin, murderer, betrayer, traitor, terrorist, revolutionary, seditionist, rebel, guerrilla(s), invader, the other side, hostile nation, hostile forces, villain, bad guy*.
A personal opponent
rival, opponent, competitor, foe, antagonist, adversary, assailant, nemesis, archenemy, bÃªte noire (French), detractor, prosecutor, inquisitor, informer, calumniator, falsifier, disputant, traducer, asperser, defiler, defamer, slanderer, backbiter, vilifier.