Faded image partly indistinct (3)
I believe the answer is:
dim
'indistinct' is the definition.
(similar in meaning)
'faded image partly' is the wordplay.
'partly' indicates a hidden word.
'DIM' is hidden in the letters of 'faded image'.
(Other definitions for dim that I've seen before include "Not bright, cloudy" , "Lacking clarity or distinctness" , "Slow-witted" , "Not brilliant" , "Not bright, poorly lit" .)