Order to leave: do so imploringly (6)
I believe the answer is:
begone
'order to leave' is the definition.
(word used to command that someone goes away)
I don't understand the remainder of the clue.
(Other definitions for begone that I've seen before include "Archaic command to go away, banish" , "Get away" , "Archaic word of dismissal" , "get lost" , "Take a hike" .)