By the sound of it, abandon course (7)
I believe the answer is:
dessert
'course' is the definition.
(I know that dessert is a type of course)
'by the sound of it abandon' is the wordplay.
'by the sound of it' shows a homophone (sound like).
'abandon' becomes 'desert' (desert can mean to leave or abandon).
'desert' sounds like 'DESSERT'.
(Other definitions for dessert that I've seen before include "Sweet, last course of a meal" , "Christmas pudding maybe" , "Fool possibly" , "Spotted Dick is one" , "Charlotte maybe" .)