흥청망청 쓰다 · 흥청망청 마시다 · 흥청망청 놀다
extravagantly, wastefully; in a reckless, merrymaking way
Example
월급을 흥청망청 쓰다가 월말에 돈이 하나도 없었어요.
I spent my paycheck recklessly and had no money left at the end of the month.
Word parts
Rhyming doubled word; compare 흥청거리다 'to make merry, splash money around.'
Good to know
Almost always with spending or partying: 돈을 흥청망청 쓰다 'to blow money.'