Disheartened actress, bored by part, whispers to audience (6)
I believe the answer is:
asides
'whispers to audience' is the definition.
I can't tell whether this defines the answer.
'disheartened actress bored by part' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters) (the middle or heart is removed).
'bored by' means one lot of letters goes inside another (to bore something can mean to drill into it).
'part' becomes 'side' (side is a kind of part).
'actress' with its centre taken out is 'as'.
'as' going around 'side' is 'ASIDES'.
Can you help me to learn more?
(Other definitions for asides that I've seen before include "Words spoken from corner of mouth" , "Words spoken through side of mouth, not for all to hear" , "Words spoken on stage" , "Players aren't meant to hear these" , "Daises (anag.)" .)