Enthusiasm to blow over (5)
I believe the answer is:
gusto
'enthusiasm' is the definition.
(I know that gusto is a type of enthusiasm)
'blow over' is the wordplay.
'blow' becomes 'gust' (as in a gust of wind).
'over' becomes 'o' (cricket abbreviation).
'gust'+'o'='GUSTO'
'to' acts as a link.
(Other definitions for gusto that I've seen before include "Great enjoyment, vigour" , "(Corporate) emblem" , "exhilaration" , "Great enthusiasm" , "Zest, exuberance" .)