Hidden talent's wasted (6)
I believe the answer is:
latent
'hidden' is the definition.
(latent can mean hidden or unused)
'talent's wasted' is the wordplay.
'wasted' is an anagram indicator.
'talent' is an anagram of 'LATENT'.
(Other definitions for latent that I've seen before include "Existing but hidden" , "Concealed - not yet developed" , "Not presently active" , "Hidden, not manifest" , "not out in the open" .)