Sub edited unfinished column (5)
I believe the answer is:
locum
'sub' is the definition.
(locum can mean a substitute)
'edited unfinished column' is the wordplay.
'edited' indicates anagramming the letters.
'unfinished' means to remove the last letter.
'column' with its last letter taken away is 'colum'.
'colum' anagrammed gives 'LOCUM'.
(Other definitions for locum that I've seen before include "Medical temp?" , "One standing in" , "Professional temp" , "Temporary deputy for doctor" , "Physician's stand-in" .)