Opening bit for spokesperson (10)
I believe the answer is:
mouthpiece
'spokesperson' is the definition.
(I know that mouthpiece is a type of spokesperson)
'opening bit' is the wordplay.
'opening' becomes 'mouth' (mouth is a kind of opening).
'bit' becomes 'piece' (synonyms).
'mouth'+'piece'='MOUTHPIECE'
'for' acts as a link.
(Other definitions for mouthpiece that I've seen before include "Spokesman" , "Spokesperson" .)