1. A person who wastes, especially one who squanders money; a spendthrift.
2. An idler; a loafer; a good-for-nothing.
Wastrel is from waste + -rel (as in scoundrel).
Horace Liveright, the book publisher of the 1920's, is usually recalled in literary memoirs as a charming wastrel, a gambler who always saw a winning bet as a chance to raise his stake in whatever game he was losing at.
-- Christopher Lehmann-Haupt, "Disastrous Life of a Pioneer in Hype", New York Times, July 27, 1995