1. Military or paramilitary groups that do not belong to the regular armed forces of a state, often operating outside conventional military structure and rules of engagement
The government struggled to control the irregular forces operating in the remote regions.
O governo teve dificuldade em controlar as forças irregulares que operavam nas regiões remotas.
2. Armed groups engaged in guerrilla warfare, insurgency, or resistance movements
Irregular forces conducted raids against the occupying army.
As forças irregulares conduziram ataques contra o exército invasor.