Partisan
wiktionary
From 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 "guerilla fighter" sense influenced by Serbo-Croatian partizan, Russian партиза́н(partizán), from the same source. [1] The sense of "guerilla fighter" is from c. 1690. The adjective in the military sense dates from the early 18th century.(Can this(+) etymology be sourced?)
From French partizaine, from Middle French partizaine, partisanne etc., from Italian partigiana, related to Etymology 1 above (apparently because it was seen as a typical weapon of such forces). [2]
etymonline
partisan (n.)
also partizan, 1550s, "one who takes part with another, zealous supporter," especially one whose judgment is clouded by prejudiced adherence to a party, from French partisan (15c.), from dialectal upper Italian partezan (Tuscan partigiano) "member of a faction, partner," from parte "part, party," from Latin partem (nominative pars) "a part, piece, a share, a division; a party or faction; a part of the body; a fraction; a function, office" (from PIE root *pere- (2) "to grant, allot").
In military use, "member of a detachment of troops sent on a special mission," from 1690s. As these commonly were irregular troops, it took on the sense of "guerrilla fighter" in the Peninsular campaign of the Napoleonic wars and again in reference to resistance to Nazi occupation in the Balkans and Eastern Europe in World War II.
partisan (adj.)
1708 in a military sense, "engaged on a special enterprise;" 1842 in politics, "of or pertaining to a party or faction;" from partisan (n.).
