One who feels hatred toward, intends injury to, or opposes the interests of another; a foe. A hostile power or force, such as a nation. A member or unit of such a force. A group of foes or hostile forces. See Usage Note at collective noun. Something destructive or injurious in its effects: "Art hath an enemy called Ignorance\u201d ( Ben Jonson). Of, relating to, or being a hostile power or force.