wicked

Definitions

General English

Slang

  • adjective good, excellent. A US term of approbation adopted by UK teenagers. Originally in black and street-gang usage, the word is now employed by analogy with bad but in this sense is probably much older, dating from the turn of the 20th century. By 1989 wicked had become a vogue term, even among primary schoolchildren (sometimes used in the emphatic form ‘well wicked’, meaning extremely good, and it may alternatively be spelled ‘wikkid’).

Origin & History of “wicked”

Wicked and witch are closely related. Wicked is an extension, using the suffix -ed, of the now obsolete adjective wick ‘wicked’. And this in turn originated as an adjectival use of Old English wicca ‘wizard’, whose feminine form is the ancestor of modern English witch.
http://www.dictionarycentral.com/definition/wicked.html