Vigour, brio (3)
I believe the answer is:
vim
This clue is a double definition.
'vigour' is the first definition.
(synonyms)
'brio' is the second definition.
(I've seen this in another clue)
(Other definitions for vim that I've seen before include "Pizazz" , "Pep (informal)" , "Pep and energy" , "Informal energy or drive" , "Energy and vigour" .)