Impasse from tired sweetheart? (9)
I believe the answer is:
stalemate
'impasse' is the definition.
(I know that impasse can be written as stalemate)
'tired sweetheart?' is the wordplay.
'tired' becomes 'stale' (I've seen this in another clue).
'sweetheart?' becomes 'mate' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'stale'+'mate'='STALEMATE'
'from' is the link.
Can you help me to learn more?
(Other definitions for stalemate that I've seen before include "Blocked position" , "Unresolvable position" , "A no-win situation in chess" , "where moving is impossible" , "Chess game deadlock" .)