Has good intentions for average balloon (5,4)
I believe the answer is:
means well
'has good intentions' is the definition.
(I've seen this before)
'average balloon' is the wordplay.
'average' becomes 'mean' (type of average).
'balloon' becomes 'swell' (I've seen this before).
'mean'+'swell'='MEANS WELL'
'for' is the link.
(Other definitions for means well that I've seen before include "full of good intentions" , "tries to be generous" .)