1. lack of restraint in spending money or use of resources: "his reckless extravagance with other people's money"Similarprofligacylack of thriftunthriftinessthriftlessnessimprovidencewastefulnesswasteoverspendingprodigalitysquanderinglavishnessimmoderationexcessrecklessnesslack of restraintirresponsibilityspendthrift behaviorfree-spending waysOppositethrift