Narrow victory keeping father excited (5-4)
I believe the answer is:
wafer-thin
'narrow' is the definition.
(I've seen this before)
'victory keeping father excited' is the wordplay.
'victory' becomes 'win' (I've seen this before).
'keeping' indicates putting letters inside.
'excited' indicates anagramming the letters.
'father' with letters rearranged gives 'aferth'.
'win' going around 'aferth' is 'WAFER-THIN'.
(Other definitions for wafer-thin that I've seen before include "Very fine" , "Very narrow" , "Having little thickness" , "Warn thief stealing slim biscuit - very slim" , "Having very little width or substance" .)