It was the movement to end slavery, and for decades it was treated as dangerous radicalism. The people who demanded immediate freedom were a hated minority, until they won.
Abolition was the movement to end slavery, and abolitionists were those who demanded it, many of them insisting on immediate and unconditional emancipation rather than gradual schemes. The word comes from the Latin abolere, to destroy or do away with.
In the early 1800s this was a fringe and despised position. Abolitionists were mobbed, their presses smashed, their mail burned. The publisher Elijah Lovejoy was murdered by a pro-slavery crowd in 1837 for printing antislavery newspapers.
The movement was powered by extraordinary voices. Frederick Douglass, who escaped slavery and became its most powerful witness; Harriet Tubman, who returned again and again to lead others out; William Lloyd Garrison, whose paper The Liberator refused all compromise.
Abolition reshaped the nation. It pushed the country toward the Civil War, helped turn that war into a war against slavery, and culminated in the Emancipation Proclamation and the Thirteenth Amendment, which finally abolished slavery in 1865.