沉湎

沉湎	chén miǎn	(literary) to wallow in; to indulge in; to be deeply engrossed in
沉	chén	variant of 沉
沉	chén	to submerge / to immerse / to sink / to keep down / to lower / to drop / deep / profound / heavy
湎	miǎn	used in 沉湎