an adherent or supporter of a person, group, party, or cause, esp. a person
who shows a biased, emotional allegiance.
2.
Military. a member
of a party of light or irregular troops engaged in harassing an enemy, esp. a
member of a guerrilla band engaged in fighting or sabotage against an occupying
army.
–adjective
3.
of, pertaining to, or characteristic of partisans; partial to a specific
party, person, etc.: partisan politics.
4.
of, pertaining to, or carried on by military partisans or guerrillas.