Despicable person (6)
'despicable person' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for wretch that I've seen before include "Someone you feel sorry for" , "A poor miserable person" , "Good-for-nothing" , "Scoundrel" , "Person in pitiful circumstances" .)
(Other definitions for toerag that I've seen before include "Despicable chap" , "Despicable person (slang)" , "O, great! (anag) -- a worthless fellow" , "Scamp" , "despicable sort" .)