"Deadlock" is hackneyed, pal (9)
I believe the answer is:
'deadlock' is the definition.
(I know that deadlock can be written as stalemate)
'hackneyed pal' is the wordplay.
'hackneyed' becomes 'stale' (I've seen this before).
'pal' becomes 'mate' (both can mean a friend).
'is' acts as a link.
(Other definitions for stalemate that I've seen before include "Deadlock, impasse" , "Inglorious deadlock" , "Blocked position" , "Possible outcome of chess game" , "where moving is impossible" .)