Manuscript marking (4)
I believe the answer is:
stet
'manuscript marking' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stet that I've seen before include "cancel amendment" , "Printing instruction: "Let it stand"" , "Editorial instruction meaning "let it stand"" , "Ignore correction" , "Leave as is - don't amend" .)