Latent ability (9)
I believe the answer is:
potential
'latent ability' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for potential that I've seen before include "Possibility, promise" , "Latent, not yet actual" , "Latent power" , "Likely, though not yet tested" , "Latent qualities that may develop" .)