Green’s Dictionary of Slang

wicked adv.

very, really.

[UK]Egan Life in London (1869) 264: Come, Lummy, von’t you stand a drap of summat, as you are in luck, and it’s a wicked could day?
[US]S. King It (1987) 376: Something hit that fucker wicked hard.
[US](con. early 1950s) J. Ellroy L.A. Confidential 283: He had to piss wicked bad.
[US](con. 1975–6) E. Little Steel Toes 106: It’s been wicked good.
[US]R. Price Lush Life 171: Still alert enough to use those wicked-quick infielder’s hands .
[SA]IOL News (Western Cape) 28 Jan.. [Internet] I’m wicked serious.
[US]T. Robinson Hard Bounce [ebook] It was true. Still sounded wicked retarded.