Dissipation; living a profligate, debauched, or wasteful life—often used in a literary or formal sense.
若いころは放蕩に明け暮れ、財産を使い果たした。
In his youth he wasted his time in debauchery and used up his fortune.
その物語は放蕩息子が改心する話だ。
The story is about a prodigal son who repents.