Contemptible dope (3-4)
I believe the answer is:
low-down
I believe this is a double definition.
'contemptible' is the first definition.
(thesaurus)
'dope' is the second definition.
(I know that dope can be written as low-down)
(Other definitions for low-down that I've seen before include "Info (slang) - dishonourable" , "Data - base" , "Inside story" , "Inside information - mean (7;3-4)" , "Mean, unfair" .)