Person at academy getting a grip on composition (6)
I believe the answer is:
sonata
'composition' is the definition.
(type of musical composition)
'person at academy getting a grip' is the wordplay.
'a grip' indicates the answer is hidden within the clue (I've seen 'gripping' mean this (the answer is held or gripped within the clue)).
'SONATA' is hidden in the letters of 'person at academy getting'.
'on' acts as a link.
(Other definitions for sonata that I've seen before include "See 6" , "Work for soloist" , "Beethoven's 'Moonlight', for example" , "composition for piano, perhaps" , "Musical work for a solo instrument" .)