enemy - an opposing military force; "the enemy attacked at dawn"

armed forces, armed services, military, military machine, war machine - the military forces of a nation; "their military is the largest in the region"; "the military machine is the same one we faced in 1991 but now it is weaker"

adversary, antagonist, opposer, resister, opponent - someone who offers opposition

besieger - an enemy who lays siege to your position

mortal enemy - an enemy who wants to kill you

challenger, competitor, contender, rival, competition - the contestant you hope to defeat; "he had respect for his rivals"; "he wanted to know what the competition was doing"