Combatant is the legal status of a person entitled to directly participate in hostilities during an armed conflict, and may be intentionally targeted by an adverse party for their participation in the armed conflict. Combatants are not afforded immunity from being directly targeted in situations of armed conflict. The legal definition of "combatant" is found at article 43(2) of Additional Protocol I (AP1) to the Geneva Conventions of 1949. It states that "Members of the armed forces of a Party to a conflict (other than medical personnel and chaplains covered by Article 33 of the Third Convention) are combatants, that is to say, they have the right to participate directly in hostilities." Consequently, on the other hand combatants, as a rule, are legal targets themselves for the opposite side regardless the specific circumstances at hand, in other words, they can be attacked regardless of the specific circumstances simply due to their status, so as to deprive their side of their support.
In addition to having the right to participate in hostilities, combatants have the right to the status of prisoners of war when captured during an international armed conflict. "While all combatants are obliged to comply with the rules of international law applicable in armed conflict, violations of these rules shall not deprive a combatant of his right to be a combatant or, if he falls into the power of an adverse Party, of his right to be a prisoner of war."
The requirement of distinction between combatants and civilians lies at the root of the jus in bello. It is reflected in Article 48 of Protocol Additional I of 1977 to the 1949 Geneva Conventions for the Protection of War Victims, entitled "Basic rule": "the Parties to the conflict shall at all times distinguish between the civilian population and combatants and between civilian objects and military objectives and accordingly direct their operations only against military objectives."
Under international humanitarian law (IHL, aka the rules of armed conflict) combatants may be classified in one of two categories: privileged or unprivileged. In that sense, privileged means the retainment of prisoner of war status and impunity for the conduct prior to capture. Thus, combatants that have violated certain terms of the IHL may lose their status and become unprivileged combatants either ipso iure (merely by having committed the act) or by decision of a competent court or tribunal. In the relevant treaties, the distinction between privileged and unprivileged is not made textually; international law uses the term combatant exclusively in the sense of what is here termed "privileged combatant".
If there is any doubt as to whether the person benefits from "combatant" status, they must be held as a POW until they have faced a "competent tribunal" (Article 5 of the Third Geneva Convention, GC III) to decide the issue.
The following categories of combatants qualify for prisoner-of-war status on capture:
For countries which have signed the "Protocol Additional to the Geneva Conventions of 12 August 1949, and relating to the Protection of Victims of International Armed Conflicts" (Protocol I), combatants who do not wear a distinguishing mark still qualify as prisoners of war if they carry arms openly during military engagements, and while visible to the enemy when they are deploying to conduct an attack against them.
Main article: Unprivileged combatant
There are several types of combatants who do not qualify as privileged combatants:
Most unprivileged combatants who do not qualify for protection under the Third Geneva Convention do so under the Fourth Geneva Convention (GCIV), which concerns civilians, until they have had a "fair and regular trial". If found guilty at a regular trial, they can be punished under the civilian laws of the detaining power.