Meaning

noun an advocate of secession or separation from a larger group (such as an established church or a national union)

adjective having separated or advocating separation from another entity or policy or attitude

originEtymology tree English separate Proto-Indo-European *-id- Proto-Indo-European *-yéti Proto-Indo-European *-idyéti Proto-Hellenic *-íďďō Ancient Greek -ῐ́ζω (-ĭ́zō) Proto-Hellenic *-tās Ancient Greek -τής (-tḗs) Ancient Greek -ῐστής (-ĭstḗs)bor. Latin -istader. Old French -istebor. Middle English -ist English -ist English separatist From separate + -ist.

Etymology from Wiktionary, CC BY-SA 3.0