See it’s an eyesore (5)
I believe the answer is:
sight
I believe this is a double definition.
'see' is the first definition.
(I've seen this before)
'an eyesore' is the second definition.
(I've seen this before)
'it's' acts as a link.
(Other definitions for sight that I've seen before include "Device used in aiming" , "something ugly" , "Sense" , "A lot" , "A great many" .)