SE in slang uses
[mid-17C] a flannel shirt.
[mid-19C] a white hat with a black band.
[1930s] (US) of a white male, to have sexual intercourse with a black female.
[early–mid-19C] a pair of black eyes.
[mid-19C–1930s] a single black eye.
1. [19C+] having a black eye; thus have one’s eyes in mourning, to have a pair of black eyes.
2. (W.I./Jam.) dirty.
3. in fig. use.
4. [late 19C+] (UK society) having dirty fingernails, edging the hands like the black border of mourning paper; thus (20C+) you’re in mourning for the cat, you have dirty fingernails.
see under peeper n.