Green’s Dictionary of Slang

(US) go away!

1954		B. Kiely Honey Seems Bitter 176: Now shag off to hell and let me go home alone.
1963		J. Rechy City of Night 150: Shag, man [...] I mean, split — Barbara dont need you guys any more.
1966		P. Boyle At Night All Cats Are Grey 196: Shag off, you big cackling jackass!
1972		J.B. Keane Letters of Irish Parish Priest 32: You shouldn’t tell those ducks shag off. Never use rotten language in front of ducks. Just say cush, cush and they’ll shag off themselves.
1989		H. Leonard Out After Dark 168: I snarled ‘Shag off!’ and flung out of the shop.
1990		R. Doyle Snapper 201: Ah, shag off.