Green’s Dictionary of Slang

1. to have diarrhoea.

1640		‘Mary Tattle-well’ Womens sharpe revenge 90: They can cough Logicke, speake Rhetoricke, [s]neefe Grammer, belch Poetry, pisse Geometry, groane Musicke, vomit Apothegmes, and squirt Oratory .
1772		Bridges Burlesque Homer (3rd edn) 30: No longer stand in doubt, / Squirting your very bowels out.
1798		‘The Blue Vein’ in Hilaria 59: Three nights and three days he lay squirting in bed.
1954		(con. 1940s) T.A.G. Hungerford Sowers of the Wind 69: We’d be squirting our guts out with dysentry.
1994		G. Indiana Rent Boy 39: Bruce is one powerful enema slave and foot slave in his chosen industry [...] Sorry. He’s never squirted on my watch.

2. to ejaculate.

2023

(con. 1962) J. Ellroy Enchanters 273: The Mirror-News constrained Morty. He couldn’t write jizz, spurt, semen, jack off, squirt.

3. (UK black/gang) to spray a victim with acid.

2018-20

T. Thorne (ed.) ‘Drill Slang Glossary’ at Forensic Linguistic Databank 🌐 Squirt - spray acid (over someone).