An abolitionist is someone who actively works to end a system they believe is unjust, especially slavery.

In its original and most common historical use, an abolitionist was a person in the 18th and 19th centuries who wanted slavery abolished by law and often campaigned, wrote, organized, or protested to make that happen. Today, people sometimes use “abolitionist” more broadly for activists who want to completely get rid of other institutions they see as harmful, such as the death penalty or certain parts of the criminal justice system, not just reform them.