black as... adj.
[mid-19C+] used in var. combs. to mean extremely black, usu. of darkness, occas. of race.
1. of an expression, frowning, glowering.
2. dirty, e.g. of a garment.
1. [late 19C] (also dark as Newgate knocker) of a night, very dark.
2. [1980s] very dirty.