Certain after a time to see deletion (7)
I believe the answer is:
erasure
'deletion' is the definition.
(I know that erasure is a type of deletion)
'certain after a time' is the wordplay.
'certain' becomes 'sure' (synonyms).
'after' means one lot of letters go next to another.
'a time' becomes 'era' (an era is a period of time).
'sure' put after 'era' is 'ERASURE'.
'to see' is the link.
(Other definitions for erasure that I've seen before include "Obliteration of data" , "Deletion by an act of expunging" , "Removal" , "Censorship" , "clearing of tape" .)