Entries linking to segregationist
1550s, "act of separating" (a sense now obsolete); 1610s, "act or action of segregating, separation from others," from Late Latin segregationem (nominative segregatio), noun of action from past-participle stem of segregare (see segregate). Meaning "state or condition of being segregated" is from 1660s. Specific U.S. sense of "enforced separation of races" is attested from 1883.
Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.