One green and largely stoned in a mostly noisy party? (7)
I believe the answer is:
avocado
'one green and largely stoned' is the definition.
(green fruit with a large stone)
'a mostly noisy party?' is the wordplay.
'mostly' means to remove the last letter (most but not all of the word).
'noisy' becomes 'vocal'.
'party?' becomes 'do' (do is a kind of party).
'vocal' with its last letter removed is 'voca'.
'a'+'voca'+'do'='AVOCADO'
'in' acts as a link.
(Other definitions for avocado that I've seen before include "Savoury pear" , "Dark green pear-shaped fruit" , "Green-fleshed fruit" , "Tropical fruit with a yellow creamy flesh" , "Green - fruit eaten as a vegetable" .)