Disinclination to act shown by one with damaged retina (7)
I believe the answer is:
inertia
'disinclination to act' is the definition.
(I've seen this before)
'one with damaged retina' is the wordplay.
'one' becomes 'i' (Roman numeral).
'with' means one lot of letters go next to another.
'damaged' indicates an anagram.
'retina' with letters rearranged gives 'nertia'.
'i'+'nertia'='INERTIA'
'shown by' acts as a link.
(Other definitions for inertia that I've seen before include "Lack of activity" , "Unresponsiveness" , "Tendency to inactivity" , "Disinclination to act" , "Apathetic state" .)