Indistinct image (4)
I believe the answer is:
blur
'indistinct image' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for blur that I've seen before include "Confused impression" , "Indistinct appearance like smear" , "Indistinct mark" , "Unclear image, of a pop band" , "Group - smudge" .)