Longman Dictionary of Contemporary English - enemy

~ n 1 someone who hates you and wants to harm you  (She's a dangerous enemy to have. | be enemies (=hate and oppose each other))  (Jake and Paul have been enemies for years. | make an enemy (of sb))  (He's a ruthless businessman and has made a lot of enemies. | sworn enemies (=enemies determined never to end their quarrel)) 2 someone who opposes you and wants to prevent you doing something  (political enemies | Greenpeace, an enemy of the chemical industry, is pressing for more environmental legislation.) 3 someone you are fighting in a war  (Our enemies were hidden in the trenches. | enemy forces (=the army, navy etc of the country that you are fighting) | enemy soldiers/aircraft)  (Enemy aircraft were spotted overhead.) 4 be your own worst enemy to behave in a way that causes problems for yourself 5 literary something that changes something else or makes it weaker  (Jealousy is the enemy of love.)