Leave Virginia to supply food? Mostly (6)
I believe the answer is:
vacate
'leave' is the definition.
(vacating is a kind of leaving)
'virginia to supply food? mostly' is the wordplay.
'virginia' becomes 'va' (US state abbreviation).
'to supply food?' becomes 'cater' (supplying food is a kind of catering).
'mostly' means to remove the last letter.
'cater' with its last letter removed is 'cate'.
'va'+'cate'='VACATE'
(Other definitions for vacate that I've seen before include "Leave (a position)" , "Move out and leave empty" , "Caveat - cease to occupy" , "Depart from, leave empty" , "Leave (a place previously occupied)" .)