Fruit and veggies primarily supplied by online grocer (7)
I believe the answer is:
avocado
'fruit' is the definition.
(avocado is a kind of fruit)
'and veggies primarily supplied by online grocer' is the wordplay.
'primarily' suggests taking the first letters.
'supplied by' says to put letters next to each other.
'online grocer' becomes 'ocado' (I can't justify this - if you can you should believe this answer much more).
The initial letters of 'and veggies' is 'av'.
'av'+'ocado'='AVOCADO'
Can you help me to learn more?
(Other definitions for avocado that I've seen before include "may be stoned" , "A posh tropical pear" , "Light green; fruit" , "Yellowish green" , "Fruity colour" .)