Scoundrel to stop supply of tea (6)
I believe the answer is:
caddie
'supply of tea' is the definition.
(tea caddie)
'scoundrel to stop' is the wordplay.
'scoundrel' becomes 'cad' (cad is a kind of scoundrel).
'to stop' becomes 'die' (I've seen this in other clues).
'cad'+'die'='CADDIE'
(Other definitions for caddie that I've seen before include "Golfer's assistant on course" , "club assistant" , "A golfer's assistant-adviser" , "Assistant to carry the golf clubs" , "Padraig Harrington's brother-in-law Ronan Flood is also his . . . . . ." .)