Jersey, possibly, with large hood (4)
I believe the answer is:
cowl
'hood' is the definition.
(I know that hood can be written as cowl)
'jersey possibly with large' is the wordplay.
'jersey possibly' becomes 'cow' (Jersey is a breed of cow).
'with' is a charade indicator (letters next to each other).
'large' becomes 'L' (eg in clothes sizes).
'cow'+'l'='COWL'
(Other definitions for cowl that I've seen before include "Hood for monk or chimney" , "Monk's hooded habit" , "Hood-shaped covering" , "Dried fruit" , "Monk's hood or chimney covering" .)