The phrase I’ll be a John Brown or I’ll be John Browned means “I’ll be damned” or “I’ll be hanged.” It’s a reference to the militant abolitionist John Brown, who in 1859 led 21 men on a raid of...
“I’ll be John Brown’s slew foot,” a euphemism for “I’ll be damned,” makes reference to the abolitionist riot leader John Brown, who was said to be damned after he was hanged. Slew in this sense means...