Meet prisoner in front of border (8)
I believe the answer is:
converge
'meet' is the definition.
(converging is a kind of meeting)
'prisoner in front of border' is the wordplay.
'prisoner' becomes 'con' (abbreviation for 'convict').
'in front of' is a charade indicator (letters next to each other).
'border' becomes 'verge' (verge is a kind of border**).
'con'+'verge'='CONVERGE'
(Other definitions for converge that I've seen before include "Approach a single point" , "Move towards meeting" , "Tend to meet at a point" , "Move towards or meet at a point" , "Come towards the same point like Congreve" .)