abolitionist n.

1520s, "act of abolishing; state of being abolished," from French abolition or directly from Latin abolitionem (nominative abolitio) "an abolition, an annulling," noun of action from past-participle stem of abolere "destroy" (see abolish). Related: Abolitionary ("destructive"); abolitional ("pertaining to abolition").

Specific application to "opposition to the trans-Atlantic African slave trade" as a political question is first attested 1788. By 1823 abolition was being used in regard to proposals or arguments to end American slavery itself, and after 1832 this was the usual sense of the word until the effort was accomplished by the 13th Amendment (1865). The alternative noun abolishment (1540s) seems not to have acquired a special use in reference to slavery issues.

word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.

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.