Brahms and Liszt refusing to defect (4)
I believe the answer is:
blot
'defect' is the definition.
(blot is a kind of defect)
'brahms and liszt refusing to' is the wordplay.
'brahms and liszt' becomes 'blotto' ('Brahms and Liszt' is rhyming slang for 'pissed').
'refusing' suggests deleting specific letters.
'blotto' with 'to' taken out is 'BLOT'.
(Other definitions for blot that I've seen before include "Smudge (on escutcheon?)" , "Spot of ink, paint etc" , "Dark mark or stain" , "Cross out; inky mess" , "stain on reputation" .)