offender, attacker, assailer, attack, assaulter, invader, assaulter, assailant.
He had not the time to reply to the audacious insult offered him by a similar one, for the three witnesses of the scene cast themselves between him and his aggressor.
But I was not the aggressor.
He had been shot at, had once been knocked off his horse, and had received various threatening letters; but it always turned out that he discovered the aggressor,
and prosecuted and convicted him.