Uttered unkind expression (4)
I believe the answer is:
mien
'expression' is the definition.
(thesaurus)
'uttered unkind' is the wordplay.
'uttered' indicates a 'sounds like' (homophone) clue.
'unkind' becomes 'mean' (I've seen this before).
'mean' sounds like 'MIEN'.
(Other definitions for mien that I've seen before include "attitude" , "Person's appearance or manner" , "person's look" , "Dignified manner" , "Facial expression sounds miserly" .)