Fabulous flyer wearing Curie’s bloomers (5)
I believe the answer is:
croci
'bloomers' is the definition.
(I've seen this before)
'fabulous flyer wearing curie's' is the wordplay.
'fabulous flyer' becomes 'roc' (I've seen this in another clue).
'wearing' indicates putting letters inside.
'curie' becomes 'Ci' (synonyms).
'roc' inserted inside 'ci' is 'CROCI'.
(Other definitions for croci that I've seen before include "they come out in spring" , "Bloomers" , "blooms" , "flowers" .)