Criminal Kew CID busted (6)
I believe the answer is:
wicked
'criminal' is the definition.
(thesaurus)
'kew cid busted' is the wordplay.
'busted' indicates anagramming the letters.
'kew'+'cid'='kewcid'
'kewcid' is an anagram of 'WICKED'.
(Other definitions for wicked that I've seen before include "Very bad, or very good nowadays" , "Morally bad or wrong" , "A candle is" , "Sinful" , "very likely to cause harm" .)