Real enthusiasts will swallow this ostentatious display (7)
I believe the answer is:
fanfare
'ostentatious display' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
(Other definitions for fanfare that I've seen before include "Ceremonial trumpet flourish" , "Short ceremonial tune for trumpets" , "Flourish played at military Ceremonial" , "Enthusiastic display" , "Naff era (anag)" .)