Criminal's cover left dump unprotected (7)
I believe the answer is:
hoodlum
'criminal's' is the definition.
(hoodlum is a kind of criminal)
'cover left dump unprotected' is the wordplay.
'cover' becomes 'hood' (hooding is a kind of covering**).
'left' becomes 'l' (common abbreviation).
'unprotected' indicates the central letters.
The middle letters of 'dump' are 'um'.
'hood'+'l'+'um'='HOODLUM'
(Other definitions for hoodlum that I've seen before include "Young thug or gangster" , "Yobbo" , "Person vandalising" , "Punk" , "tough!" .)