Green’s Dictionary of Slang

blow! excl.²

go away!

1926		Maines & Grant Wise-crack Dict. 6/1: Blow! – The skin game man’s signal to his confederates to lose at the game.
1934		(con. 1920s) J.T. Farrell Young Manhood in Studs Lonigan (1936) 164: ‘Hey, punk, blow!’ Studs commanded.
1948		H. McCoy Kiss Tomorrow Goodbye in Four Novels (1983) 265: You like your job? You wanna keep it? Then blow.
1954		R. Mais Brother Man (1966) 154: You wanna do me a favour? Blow.
1959		A. Zugsmith Beat Generation 26: ‘Blow, will you?’ he told Jester.
1967		A. Baraka Tales (1969) 14: Aww, man, blow, will you?
1983		S. King Christine 148: Take your bad jokes and get lost, kid. Blow.