An attacker is someone who initiates an offensive action against another person or group. The term can be used to describe a variety of different people, from an ENEMY (5 letters) who is actively hostile towards another, to an ANTAGONIST (10 letters) who is in opposition to another, to an OPPONENT (8 letters) who is engaged in a contest with another, to a MUGGER (6 letters) who uses violence to take something from another, to an ADVERSARY (9 letters) who is an OPPONENT in a conflict, to an INVADER (7 letters) who enters a territory by force, to an AGGRESSOR (9 letters) who initiates a conflict, to a FOE (3 letters) who is an ENEMY or OPPONENT, to an ASSAILANT (9 letters) who attacks another, to a RAIDER (6 letters) who makes a sudden attack.