From Longman Dictionary of Contemporary Englishspendthriftspend‧thrift /ˈspendˌθrɪft/ noun [countable] SPEND MONEYsomeone who spends money carelessly, even when they do not have a lot of it
Examples from the Corpus
spendthrift• If the Tories are seeking to portray Mr Brown as a spendthrift, they are almost certain to fail.• She was by no means a spendthrift, but somehow all the money disappeared anyway.• Pedro hated his son when he was a spendthrift, and loves him when he is not.• A spendthrift with a regular, secure income is an object of desire among bankers.• Walsh was accused of everything from being a partisan zealot to an incompetent spendthrift.• I remember him as a charming but irresponsible spendthrift.• Walter Carew had placed the painting of himself further down, dissociating himself from his weaker, lecherous, spendthrift brother.• Certainly not for a wasteful spendthrift, who preyed upon a gullible old woman!• Although most Tillers were spendthrifts and never had a ha'penny or cent to their names, Florence was a financial wizard.From Longman Business Dictionaryspendthriftspend‧thrift /ˈspendˌθrɪft/ noun [countable] someone who spends money in a careless and wasteful way, even when they do not have a lot of itOrigin spendthrift (1500-1600) spend + thrift “money saved” ((14-19 centuries)) 