"Spends foolishly" is an expression that refers to someone who irresponsibly uses money, often to the point of wasting it. There are several synonyms that can be used to describe this behavior, including splurging, squandering, lavishing, frittering away, and wasting. Splurging refers to spending a large amount of money on something luxurious or unnecessary. Squandering suggests wasting money on things that are unnecessary or frivolous. Lavishing refers to spending an excessive amount of money on oneself or others. Frittering away highlights mindlessly spending small amounts of money repeatedly. Wasting, on the other hand, indicates spending money in a way that does not provide any benefit or value.