Ungenerous-sounding manner (4)
I believe the answer is:
mien
'manner' is the definition.
(mien can mean a manner or attitude)
'ungenerous-sounding' is the wordplay.
'ungenerous' becomes 'mean' (similar in meaning).
'sounding' indicates a 'sounds like' (homophone) clue.
'mean' sounds like 'MIEN'.
(Other definitions for mien that I've seen before include "Person's bearing" , "Counterance - mine?" , "Facial expression sounds miserly" , "The carriage" , "A manner like mine" .)