Correct last of errors in project (4)
I believe the answer is:
just
'correct' is the definition.
(thesaurus)
'last of errors in project' is the wordplay.
'last of' indicates one should take the final letters.
'in' is an insertion indicator.
'project' becomes 'jut' (I've seen this in another clue).
The last letter of 'errors' is 's'.
's' put within 'jut' is 'JUST'.
(Other definitions for just that I've seen before include "Barely - deserved" , "By a whisker" , "Merited" , "Simply - fair" , "legal?" .)