Exciting quality (5)
I believe the answer is:
oomph
'exciting quality' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oomph that I've seen before include "Get-up-and-go" , "Vitality - sex appeal (informal)" , "Informal energy or enthusiasm, usually in a girl" , "Dynamism" , "attractiveness" .)