Tart is trying, displaying prowess (8)
I believe the answer is:
artistry
'prowess' is the definition.
('artistry' can be a synonym of 'prowess')
'tart is trying displaying' is the wordplay.
'displaying' says the answer is hidden in the clue.
'ARTISTRY' is hidden in the letters of 'tart is trying'.
(Other definitions for artistry that I've seen before include "Creative flair" , "ability" , "Genius" , "Creativity" , "Finesse" .)