noun
indulging in evil deeds; being steeped in vice
A strong, somewhat literary expression for someone who habitually commits evil acts without restraint. Often used in moral or religious contexts.
彼は悪行三昧の人生を送った。
He led a life steeped in evil deeds.
Compound of 悪行 (evil deeds) and 三昧 (absorption, devotion), originally from the Buddhist term samādhi, extended to mean 'being absorbed in' something. The exact historical derivation is uncertain, but the word follows a common pattern of attaching 三昧 to a noun to indicate indulgence.