factionalist
/ˈfakʃ(ə)nəlɪst/ /ˈfakʃ(ə)n(ə)lɪst/ /ˈfakʃən(ə)lɪst/noun
A member or supporter of a faction, a person involved in factionalism; a creator or leader of a faction.
adjective
Of, relating to, or characteristic of factionalists or factionalism.
Origin
Late 19th century; earliest use found in Sunday Herald (Syracuse, New York). From factional + -ist.