Those to keep closer

• Battling sides
• The Sith, to the Jedi
• Adams and Jefferson, e.g.
• The Bloods and the Crips, e.g
• Calhoun and Van Buren
• Hostile parties
• Foes
• "A man cannot be too careful in the choice of his ___": Wilde
• Pakistan and India, e.g.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Enemy \En"e*my\, n.; pl. Enemies . [OF. enemi, F. ennemi, from L. inimicus; in- (negative) + amicus friend. See Amicable .] One hostile to another; one who hates, and desires or attempts the injury of, another; a foe; an adversary; as, an enemy of or to ...