Pretentious talk to fail a good man (7)
I believe the answer is:
bombast
'pretentious talk' is the definition.
(I've seen this in another clue)
'fail a good man' is the wordplay.
'fail' becomes 'bomb' (synonyms).
'good man' becomes 'st' (abbreviation for saint).
'bomb'+'a'+'st'='BOMBAST'
'to' is the link.
(Other definitions for bombast that I've seen before include "pretentious speech" , "verbosity" , "Pretentious talk" , "Pompous talk" , "Empty inflated language" .)