Abolitionist (noun)

1. A person who advocates or works for the abolition of slavery, or any other system or practice.
2. A person who supports the abolition of a particular thing.

Origin:

Late 18th century; earliest use found in the monthly magazine. from abolition + -ist.

Examples:

1. Frederick Douglass was a famous abolitionist who fought for the rights of enslaved African Americans.
2. Many abolitionists in the 19th century worked to end the transatlantic slave trade.
3. Abolitionists in the United States sought to end the practice of slavery in the country.
4. The abolitionist movement in the United Kingdom was led by figures like William Wilberforce.
5. Some contemporary abolitionists are working to end the death penalty and other forms of state-sanctioned killing.