Longing to fill a large earthenware jug (7)
I believe the answer is:
pitcher
'earthenware jug' is the definition.
(I've seen this before)
'longing to fill a' is the wordplay.
'longing' becomes 'itch' (I've seen this in other clues).
'to fill' is an insertion indicator.
'a' becomes 'per' (eg 'one a day' means 'one per day').
'itch' placed within 'per' is 'PITCHER'.
'large' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for pitcher that I've seen before include "Large jug; thrower" , "Baseball player; big jug" , "One throwing" , "one getting walked all over?" , "Vessel with a handle and spout" .)