Leave Virginia about ten, not noon (6)
I believe the answer is:
vacate
'leave' is the definition.
(vacating is a kind of leaving)
'virginia about ten not noon' is the wordplay.
'virginia' becomes 'va' (US state abbreviation).
'about' becomes 'ca' (abbreviation for 'circa'**).
'not' suggests deleting specific letters.
'noon' becomes 'n'.
'ten' with 'n' taken out is 'te'.
'va'+'ca'+'te'='VACATE'
(Other definitions for vacate that I've seen before include "Leave (a position)" , "Quit" , "Depart from, leave empty" , "Make empty" , "Caveat - cease to occupy" .)