noun.
A person who favors the abolition of some law, institution, or custom.
the GNU version of the Collaborative International Dictionary of English
noun.
A person who favors the abolition of any institution, especially negro slavery.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
a reformer who favors abolishing slavery
Word Usage
"The main abolitionist organization in the U.S. was the The American Missionary Association, indenominational Christian but growing out of the evangelical movement."