slave driver

an overseer of slaves.

a hard taskmaster: His boss was a slave driver.

Origin of slave driver

An Americanism dating back to 1800–10

It was the slave-driver speaking, the man who governed with a whip.

Captain Blood |Rafael Sabatini
The slave-driver ran over with a roar, raising his whip, while the slow rotation of the wheel carried Jason away.

The Ethical Engineer |Henry Maxwell Dempsey
I beheld my dear sister in the hands of a slave-driver, and compelled to submit to his cruelty!

The Narrative of William W. Brown, a Fugitive Slave |William Wells Brown
"One half hour to get breakfast and Miss Herne's back hair down," Mr. Rooney said, with the callousness of a slave-driver.

Blue-grass and Broadway |Maria Thompson Daviess

Next came a swaggering bully of a slave-driver, evidently bred in the North.

Lands of the Slave and the Free |Henry A. Murray

slave-driver

(esp formerly) a person forcing slaves to work

an employer who demands excessively hard work from his employees