Lowly-sounding bearing (4)
I believe the answer is:
mien
'bearing' is the definition.
(synonyms)
'lowly-sounding' is the wordplay.
'lowly' becomes 'mean'.
'sounding' indicates a 'sounds like' (homophone) clue.
'mean' sounds like 'MIEN'.
(Other definitions for mien that I've seen before include "A face like mine" , "Air - look - manner" , "person's look" , "aspect" , "Person's bearing" .)