Plead with a person to get lost (6)
I believe the answer is:
begone
'get lost' is the definition.
(I've seen this before)
'plead with a person' is the wordplay.
'plead with' becomes 'beg' (I've seen this in another clue).
'a person' becomes 'one'.
'beg'+'one'='BEGONE'
'to' is the link.
(Other definitions for begone that I've seen before include "Archaic word of dismissal" , "Archaic injunction to go away" , "Archaic command to go away, banish" , "shove off" , "get lost" .)