'Badge' -- flash number, good stuff (8)
I believe the answer is:
monogram
'badge' is the definition.
(thesaurus)
'flash number good stuff' is the wordplay.
'flash' becomes 'mo' (both mean a very short period of time).
'number' becomes 'no' (abbreviation).
'good' becomes 'g' (abbreviation).
'stuff' becomes 'ram' (ram can mean to stuff or push).
'mo'+'no'+'g'+'ram'='MONOGRAM'
(Other definitions for monogram that I've seen before include "Embroidered motif" , "Motif of interwoven letters" , "A person's initials combined in one design" , "Initials mark" , "union of characters" .)