Grill family's large vegetable (7)
I believe the answer is:
pumpkin
'large vegetable' is the definition.
'pumpkin' can be an answer for 'vegetable' (I've seen this before). I'm not sure about the 'large' bit.
'grill family's' is the wordplay.
'grill' becomes 'pump' (I've seen this in other clues).
'family' becomes 'kin' (synonyms).
'pump'+'kin'='PUMPKIN'
Can you help me to learn more?
(Other definitions for pumpkin that I've seen before include "It's a Halloween tradition" , "Large variety of squash" , "Large type of gourd" , "Halloween vegetable" , "coach would appear at midnight" .)