Definition from Wiktionary, the free dictionary
- Supporting slavery.
1902, John Lord, Beacon Lights of History, Volume XII:
- By 1835 the excitement was at its height, and especially along the line of the moral and religious argumentation, where the proslavery men met talk with talk.
1918, Carter G. Woodson, A Century of Negro Migration:
- When it seemed later that the cause of freedom would eventually triumph the proslavery element undertook to perpetuate slavery through a system of indentured servant labor.