Green’s Dictionary of Slang

grind v.

1. in the context of sex .

(a) [mid-16C+] (also grine) to have sexual intercourse; thus grinding n.; of a man, grind one’s tool v.

(b) [1920s+] (US) to rotate the hips in a sensuous manner while dancing.

(c) [1940s+] to rub one’s body, esp. the genital area, against one’s partner while dancing; thus grinding n.

2. to work laboriously; to exhaust oneself.

(a) [mid-19C+] (also grind it) to work hard, esp. at an unrewarding but necessary task; thus grinding n.

(b) [late 19C–1900s] to cause someone to work hard; thus grinder, a hard taskmaster.

(c) [mid-19C+] to devote an unreasonable amount of time and effort to one’s studies.

(d) [late 19C–1900s] to tire, to exhaust; to annoy.

(e) [1930s] (US Und.) of a confidence man, to devote a great deal of time to persuading a potential victim.

(f) (US drugs) to sell drugs.

3. to speak mockingly or persuasively.

(a) [late 19C–1900s] to ridicule, to satirize.

(b) [1920s–30s] (US) to tout a carnival sideshow; thus grindman n., a barker.

4. [1980s+] (US campus) to eat, to have some food; thus as n., an event where a large amount of food is consumed.

In derivatives

grindage (n.) [-age sfx]

[1990s+] (US teen) food.

In phrases

grind coffee (v.) [1920s–60s] (US)

1. to rotate one’s hips during intercourse; thus coffee grinder n.

2. to rotate one’s hips in a manner suggestive of copulation.

grind off (v.)

to masturbate.

grind someone’s coffee (v.) (also grind the coffee for someone)

[1920s] (orig. US black) to have sexual intercourse with.