Moves to mate, perhaps willing to support objective (7)
I believe the answer is:
endgame
'moves' is the definition.
(I have seen 'final moves' mean 'endgame' so perhaps 'moves' could also mean 'endgame')
'willing to support objective' is the wordplay.
'willing' becomes 'game' (game can mean willing to do something).
'to support' means one lot of letters go next to another (in a down clue, some letters hold others up).
'objective' becomes 'end' (both can mean a purpose).
'game' put after 'end' is 'ENDGAME'.
'to mate perhaps' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for endgame that I've seen before include "Closing chess moves" , "Beckett play" , "moves before mating" , "contest's final stage" , "close to board meeting" .)