Large jar picked up (5)
I believe the answer is:
great
'large' is the definition.
(I know that large can be written as great)
'jar picked up' is the wordplay.
'jar' becomes 'grate' (make unpleasant sound).
'picked up' shows a homophone (sound like).
'grate' is a homophone of 'GREAT'.
(Other definitions for great that I've seen before include "Extensive; excellent" , "Large, outstanding" , "Large, important" , "Dickens novel about Pip" , "Important; immense" .)