x, v.¹ — Green’s Dictionary of Slang

x v.¹

also ex

[x, a cross, thus cross out]

(Aus./US campus) to stop, to eliminate.

1957		D. Niland Call Me When the Cross Turns Over (1958) 126: Even ex the lot out and give you the whole blank page to yourself – if that’d make you happy.
1983		Eble Campus Sl. Nov. 5: x-ed – obliterated: John’s x-ed from my life.
1996		Eble Sl. and Sociability 34: x ‘to stop or eliminate’ (‘My mom x-ed my idea about hitchhiking to Florida’).