Brave face on prisoner (8)
I believe the answer is:
confront
'brave' is the definition.
(thesaurus)
'face on prisoner' is the wordplay.
'face' becomes 'front' (front is a kind of face**).
'on' says to put letters next to each other.
'prisoner' becomes 'con' (abbreviation for 'convict').
'front' after 'con' is 'CONFRONT'.
(Other definitions for confront that I've seen before include "Face in opposition" , "Oppose head-on" , "Face up to (a problem)" , "Challenge" , "Square up to" .)