Unsavoury scoundrel (3,3)
I believe the answer is:
bad egg
'scoundrel' is the definition.
(both can mean an unpleasant person)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bad egg that I've seen before include "A real stinker?" , "Dishonest person like addled ovoid" , "Was the cartoon curate presented with one" , "Untrustworthy type (smelling rotten?)" , "Worthless person" .)