a person who is actively opposed or hostile to someone or something:the traditional enemies of his tribeNigel made many enemiesthis man was her sworn enemy
(the enemy) [treated as singular or plural] a hostile nation or its armed forces, especially in time of war:the enemy shot down four helicopters [as modifier]:enemy aircraft
a thing that harms or weakens something else:routine is the enemy of art
be one's own worst enemy
act in a way contrary to one’s own interests:I try my best, but he’s his own worst enemy
make an enemy of
cause (someone) to start feeling hostile to one:you really don’t want to make an enemy of your girlfriend’s best mate