A snag over admitting curtailment of party spirit (7)
I believe the answer is:
bravura
'spirit' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
(Other definitions for bravura that I've seen before include "Style of music requiring brilliant technique" , "Display of boldness" , "Performed with daring" , "Brilliance - dash" , "Brilliant performance as in music, sounds bold" .)