spendthriftPronunciation: /ˈspɛn(d)θrɪft/Translate spendthrift | into French | into German | into Italian | into Spanish Definition of spendthrift noun a person who spends money in an extravagant, irresponsible way: Putt was a spendthrift and a heavy gambler [as modifier]:a spendthrift unclespendthrift in other Oxford dictionaries Definition of spendthrift in the US English dictionary