Use 'combatant' when referring to people directly engaged in warfare or specific conflicts. During the ceasefire, all combatants remained in their positions.
Pro Tip 2/3
Neutral Term
'Combatant' is a neutral term and doesn't imply which side of the conflict the person is on. The peace talks involved representatives from all combatants in the region.
Pro Tip 3/3
Non-Combatant Contrast
Distinguish between 'combatant' for fighters and 'non-combatant' for civilians or unarmed military personnel. Relief agencies are focused on providing aid to the non-combatants affected by war.