Progress hampered by setter repeatedly leading to deadlock (7)
I believe the answer is:
impasse
'deadlock' is the definition.
(synonyms)
'progress hampered by setter repeatedly leading' is the wordplay.
'setter repeatedly' can mean two replacements for 'setter'.
'progress' becomes 'pass' (passing is a kind of progressing).
'hampered by' indicates putting letters inside.
'setter' becomes 'me' (the setter of the clue).
'setter' becomes 'i' (the person that set the crossword).
'leading' is a charade indicator (letters next to each other).
'pass' inserted inside 'me' is 'mpasse'.
'mpasse' put after 'i' is 'IMPASSE'.
'to' acts as a link.
(Other definitions for impasse that I've seen before include "No progress is possible in this type of situation" , "Standstill" , "hopeless situation?" , "failure to progress" , "Maybe gridlock" .)