Setter is no longer cool in standstill (7)
I believe the answer is:
impasse
'standstill' is the definition.
(I know that standstill can be written as impasse)
'setter is no longer cool' is the wordplay.
'setter is' becomes 'I'm' (the setter is the person who set the crossword).
'no longer cool' becomes 'passe' (I've seen this in another clue).
'im'+'passe'='IMPASSE'
'in' is the link.
(Other definitions for impasse that I've seen before include "Stalling of negotiations" , "hopeless situation?" , "deadlock results" , "Stand-off, stalemate" , "I permit no further progress" .)