monkey on one's back noun2 •(figurative) An addiction, especially to narcotic drugs.Prine's balladeering also includes social comment, as in Sam Stone, a song about a veteran returning from "the conflict overseas with a Purple Heart and a monkey on his back." — 1972 •(figurative) A state of persistent distress or worry or the cause of such a state."'E's got th' monkey on 'is back ower this letter job," said the father secretly to me. — 1922
