Proofreader's instruction (4)
I believe the answer is:
stet
'proofreader's instruction' 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 "Editorial instruction meaning "let it stand"" , "leave things as they were" , "Notation meaning leave as is, don't alter spelling" , "Notation meaning as is, thus" , "Ignore instruction to change" .)