Are initially not entirely vocal over party fruit (7)
I believe the answer is:
avocado
'fruit' is the definition.
(avocado is a kind of fruit)
'are initially not entirely vocal over party' is the wordplay.
'initially' indicates taking the first letters.
'not entirely' means to remove the last letter (not all of the word).
'over' says to put letters next to each other.
'party' becomes 'do' (do is a kind of party).
The first letter of 'are' is 'a'.
'vocal' with its final letter removed is 'voca'.
'a'+'voca'+'do'='AVOCADO'
(Other definitions for avocado that I've seen before include "Tropical salad ingredient" , "Pear-shaped tropical fruit" , "Ingredient of guacamole" , "Green - fruit eaten as a vegetable" , "slightly green" .)