Group banned from being heard (4)
I believe the answer is:
band
'group' is the definition.
(band can mean a group of people)
'banned from being heard' is the wordplay.
'from being heard' indicates a 'sounds like' (homophone) clue.
'banned' sounds like 'BAND'.
(Other definitions for band that I've seen before include "A collection of musicians in ring" , "Pop group, perhaps" , "company" , "Group; frequency range" , "troop" .)