Contemptible one (5)
I believe the answer is:
louse
'contemptible one' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for louse that I've seen before include "Rogue" , "scum" , "Wingless parasitic insect" , "Unpleasant person" , "Wingless bloodsucker" .)