Money is jolly good (7)
I believe the answer is:
capital
I believe this is a double definition.
'money' is the first definition.
(I've seen this in another clue)
'jolly good' is the second definition.
(I've seen this in another clue)
'is' is the link.
(Other definitions for capital that I've seen before include "Money saved or invested - seat of government" , "It's excellent in the big city" , "Wellington, say" , "A big letter, or a big city" , "liquid assets" .)