Il dépense à tort et à travers.
eel day-pah sah taw ray ah trah-VAIR. Click below to hear this.*
He spends wildly.
Sounds a bit as if he’s doing some crazy thinking! After all, if penser means to think, and dé- means un-, then dépenser must mean to unthink, right?
Nah. You’re smarter than that. Dépenser means to spend. The only connection with thinking is whether you think before you spend. Which, apparently, this fellow does not do.
À tort et à travers is a fixed expression, but each half of it also exists independently. À tort means wrongly, and can be used with verbs like dire, faire, and many others.
À travers means across, through, as in à travers champs, across the fields or across country.
Together, the expression means wildly, crazily, with the implication that he does not quite have all his senses about him. He spends without thinking whether he needs this or not. He spends because some part of him needs to do it, or just because he can.
*Some mobile phones, such as Blackberries, won’t display the audio player. If no player appears, here’s an alternative link to the audio file: