noun / adjective
guerrilla
guh-RIL-uh/ɡəˈrɪlə/
An irregular fighter relying on surprise against a larger force.
The guerrilla moves cautiously through the woodland with a small group of irregular fighters.

Etymology
Literally “little war,” guerrilla named skirmishing warfare and a body of skirmishers. English extended that collective or tactical meaning to an individual fighter using irregular tactics.
More examples
- The guerrillas hide in the hills between raids on government forces.
- The larger army struggles to defend against guerrilla attacks.
- The small company uses guerrilla marketing to attract attention cheaply.
Forms
guerrilla · guerrillas