enemy combatant
Legal and military term for a person who takes part in hostilities against one's own forces. Used in contexts such as international humanitarian law and rules of engagement.
International humanitarian law has clear provisions regarding the treatment of enemy combatants.
They were detained as enemy combatants.
Compound of 敵性 (hostile nature) + 戦闘員 (combatant). The exact historical derivation is uncertain; the term is used in modern legal and military contexts.