noun
prodigal son; good-for-nothing son; profligate son
A yojijukugo describing a son who wastes money and leads a dissolute life, often causing trouble for his family. Carries a strong negative judgment.
彼は放蕩息子で、親の財産を使い果たした。
He is a prodigal son who squandered his parents' fortune.
Compound of 放蕩 (profligacy, debauchery) and 息子 (son). The exact historical origin is uncertain, but it is a straightforward descriptive yojijukugo.