Let it stand new test (4)
I believe the answer is:
stet
'let it stand' is the definition.
(I've seen this before)
'new test' is the wordplay.
'new' indicates anagramming the letters.
'test' is an anagram of 'STET'.
(Other definitions for stet that I've seen before include "Let it stand (L)" , "Ignore crossing" , "As written, don't change" , "Let it stand - printer's mark" , "Printing instruction: "Let it stand"" .)