the word "spendthrift" is a compound formed from two english words of contrasting meanings. "spend," of latin origin via old english, means to pay out or use money. "thrift," of old norse origin, originally meant prosperity and later came to signify careful management of money. the compound, which emerged in the early 17th century, ironically combines these elements to denote a person who spends the wealth that was carefully accumulated or should be carefully managed. its logic is inherently paradoxical, highlighting wasteful behavior by juxtaposing it with the concept of frugality.

Structure: spend + thrift spend: from old english spendan (borrowed from latin expendere, "to weigh out, pay out"). functional role: verb root meaning "to pay out, use up". thrift: from middle english thrift, from old norse þrift, meaning "prosperity, condition of thriving". functional role: noun meaning "economy, good management".