Jars greased by cheese (4,5)
I believe the answer is:
sage derby
'cheese' is the definition.
(I've seen this before)
'jars greased by' is the wordplay.
'jars' indicates anagramming the letters (the letters must be shocked or jarred).
'greased' is an anagram of 'sageder'.
'sageder'+'by'='SAGE DERBY'
(Other definitions for sage derby that I've seen before include "Greenish cheese" , "Cheese made with herb" , "Food" , "Green-veined cheese" .)