Green’s Dictionary of Slang

mourning n.

SE in slang uses

In compounds

mourning shirt (n.) [such a shirt needs less regular washing, ref. to the custom of wearing the same clothes through the immediate period of mourning]

[mid-17C] a flannel shirt.

In phrases

butcher’s mourning (n.) [the normal mourning hat was black, but butchers apparently disliked the colour]

[mid-19C] a white hat with a black band.

dress it in mourning (v.)

[1930s] (US) of a white male, to have sexual intercourse with a black female.

full suit of mourning (n.) (also suit of mourning)

[early–mid-19C] a pair of black eyes.

half-mourning (n.) [play on in mourning ]

[mid-19C–1930s] a single black eye.

in mourning (also full mourning) [the wearing of black as a sign of mourning; the SE adj. mourning, visibly bruised, is SE from 18C]

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.