expression, godan verb (-ru)
be pleased with oneself; gloat; bask in self-satisfaction
Describes someone indulging in their own happiness or success, often with a self-satisfied or smug tone. Similar to 悦に入る, but 浸る emphasizes being steeped in that feeling.
See also: 悦に入る
彼は自分の成功に悦に浸っている。
He is basking in the satisfaction of his own success.
ライバルの失敗を聞いて、悦に浸るわけにはいかない。
Hearing about my rival's failure, I shouldn't gloat over it.