Go over imperfection (6)
I believe the answer is:
defect
I believe this is a double definition.
'go over' is the first definition.
(I've seen this before)
'imperfection' is the second definition.
(defect is a kind of imperfection)
(Other definitions for defect that I've seen before include "Blemish, fault" , "weakness" , "Go over to the enemy - it's a flaw" , "Desert - blemish" , "'Flaw, imperfection (6)'" .)