partisan

noun

1. An adherent to a party or faction.

   “"Strong partisans of neither party, Indiana farmers failed to act as a block […]"”

2. A fervent, sometimes militant, supporter or proponent of a party, cause, faction, person, or idea.
3. A member of a band of detached light, irregular troops acting behind occupying enemy lines in the ways of harassment or sabotage; a guerrilla fighter.
4. (archaic)The commander of a body of detached light troops engaged in making forays and harassing an enemy.
5. (historical)A long-handled spear with a triangular, double-edged blade having lateral projections, in some forms also used in boar hunting.

   “I had as lief have a reed that will do me no service as a partisan I could not heave.”

   “Salisbury and his attendants were also now drawing near, with bills and partisans brandished, and bows already bended.”

6. (obsolete)A soldier armed with such a weapon.

adj

1. Serving as commander or member of a body of detached light troops.

   “partisan officer, partisan corps”

2. Adherent to a party or faction; especially, having the character of blind, passionate, or unreasonable adherence to a party.

   “They were blinded by partisan zeal.”

   “Having put partisan interests to one side, Greenwood set about making teamwork a watchword for her chairmanship, while seeking the broadest possible participation in subsequent inquiries.”

3. Devoted to or biased in support of a party, group, or cause.

   “partisan politics”

   “England will regard it as a measure of justice for Frank Lampard's disallowed goal against Germany in Bloemfontein at the 2010 World Cup - but it was also an illustration of how they rode their luck for long periods in front of a predictably partisan home crowd.”

   “He finds, not “demigods” but “a combative group of exhausted, drunken, broken, petty, partisan, scheming, squabbling, bloviating, sensory-deprived, underoxygenated, fed-up, talked-out, overheated delegates so distraught they threatened violence, secession.”