黑沉沉

pitch-black

abbr. for Heilongjiang province 黑龍江|黑龙江[Hei1 long2 jiang1]

black / dark / sinister / secret / shady / illegal / to hide (sth) away / to vilify / (loanword) to hack (computing)

to submerge / to immerse / to sink / to keep down / to lower / to drop / deep / profound / heavy

deeply / heavily