Vacuous actor friend enthrals Universal by means of audition (7)
I believe the answer is:
aurally
'by means of audition' is the definition.
I can't judge whether this definition defines the answer.
'vacuous actor friend enthrals universal' is the wordplay.
'vacuous' says to hollow out the word (remove centre letters).
'friend' becomes 'ally' (an ally is a friend or supporter).
'enthrals' is an insertion indicator.
'universal' becomes 'U' (film certificate).
'actor' with its middle removed is 'ar'.
'ar'+'ally'='arally'
'arally' going around 'u' is 'AURALLY'.
Can you help me to learn more?
(Other definitions for aurally that I've seen before include "Via the ear" , "connected with hearing" , "How one may learn" .)