hors de combat
Combatants who are hors de combat are out of the fight are and entitled to respect for their lives and physical and moral integrity. They are to be protected and treated humanely, without adverse discrimination. (Convention I Art. 3; Protocol I, Art. 4)
Attacking a person who is hors de combat is a grave breach of the Geneva Conventions. (Protocol I, Art. 85, Sec. 3)
Persons are hors de combat if they have been captured, if they have surrendered, or if they are unconscious or otherwise incapacitated provided that they do not attempt to fight or escape. (Protocol I, Art. 41, Sec. 2)
Parachutists who eject from a damaged aircraft cannot be attacked while they are descending. (Protocol I, Art. 42, Sec. 1)
Parachuters who have landed in hostile territory must be given a chance to surrender, unless they are clearly acting hostile. (Protocol I, Art. 42, Sec. 2)