Bond is back, welcoming 'Vote leave' (4)
I believe the answer is:
exit
'leave' is the definition.
(I know that leave can be written as exit)
'bond is back welcoming vote' is the wordplay.
'bond' becomes 'tie' (both can mean a connection).
'is back' says the letters should be written in reverse.
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'vote' becomes 'x' (how votes are marked).
'tie' written backwards gives 'eit'.
'eit' enclosing 'x' is 'EXIT'.
(Other definitions for exit that I've seen before include "Way out sign" , "Actor's departure" , "Depart" , "Escape route?" , "Player's departure" .)