hostile actor

• adversaryEnemy in conflict
• enemyHostile opposing party
• threatIndication of potential harm
• attackerOne who strikes first
• aggressorOne who initiates conflict

antagonist · saboteur · infiltrator · intruder · malicious · menace · spy · hacker · combatant · foe · assailant · perpetrator · provocateur · invader · villain · operative · militant · terrorist

• Aggressorsaggressor, attacker, invader, assailant, warmonger
• secret operativesspy, secret agent, double agent, infiltrator, sleeper agent