Meaning

noun a fervent and even militant proponent of something

noun an ardent and enthusiastic supporter of some person or activity

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

originFrom French partisan, from Italian partigiano (“defender of a party”), from parte (“part”). Doublet of partigiano. Attested in English from the late 15th century in the noun sense of "party adherent", and in related adjective senses from the 16th century. The "guerrilla fighter" sense influenced by Serbo-Croatian partizan, Russian партиза́н (partizán), from the same source. The sense of…

Etymology from Wiktionary, CC BY-SA 3.0