Blow in bursts with old verve (5)
I believe the answer is:
gusto
'verve' is the definition.
(I've seen this before)
'blow in bursts with old' is the wordplay.
'blow in bursts' becomes 'gust'.
'with' says to put letters next to each other.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'gust'+'o'='GUSTO'
(Other definitions for gusto that I've seen before include "Zest, exuberance" , "Relish - zest" , "(Corporate) emblem" , "Zest, great enjoyment in doing" , "Zest, pleasure in action" .)