Supply foul lice with raw vegetable (11)
I believe the answer is:
cauliflower
'vegetable' is the definition.
(cauliflower is a kind of vegetable)
'supply foul lice with raw' is the wordplay.
'supply' indicates anagramming the letters (in a supple way).
'with' is a charade indicator (letters next to each other).
'foul'+'lice'='foullice'
'foullice' after 'raw' is 'rawfoullice'.
'rawfoullice' with letters rearranged gives 'CAULIFLOWER'.
(Other definitions for cauliflower that I've seen before include "Battle-scarred lug" , "Large vegetable of cabbage family" , "Food item" , "curds" , "Variety of cabbage" .)