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.
[1990s+] (US teen) food.
1. to rotate one’s hips during intercourse; thus coffee grinder n.
2. to rotate one’s hips in a manner suggestive of copulation.
[1920s] (orig. US black) to have sexual intercourse with.
see tighten someone’s jaw(s) under jaw n.