Corporation upset with journalist being silenced (5)
I believe the answer is:
muted
'being silenced' is the definition.
(I've seen this in another clue)
'corporation upset with journalist' is the wordplay.
'corporation' becomes 'tum' ('corporation' can humorously mean belly fat).
'upset' says the letters should be written in reverse.
'with' says to put letters next to each other.
'journalist' becomes 'ed' (short for editor).
'tum' back-to-front is 'mut'.
'mut'+'ed'='MUTED'
(Other definitions for muted that I've seen before include "Viola is sometimes" , "Piano" , "Dull" , "Muffled, subdued" , "(Of colour) subdued" .)