partisan

Adjective

• devoted to a cause or party

Noun

• a pike with a long tapering double-edged blade with lateral projections; 16th and 17th centuries

• an ardent and enthusiastic supporter of some person or activity

• a fervent and even militant proponent of something

Related words

• Synonyms: 
  partizan , enthusiast , zealot , drumbeater
• Antonyms: 
  nonpartisan , nonpartizan