And, I guess, flashiness is out (9)
I believe the answer is:
gaudiness
'out' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'and i guess flashiness' is the wordplay.
'and i guess' anagrams to 'GAUDINESS'.
But, I'm not clear how this is indicated.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for gaudiness that I've seen before include "Tasteless showiness" , "Ostentation" .)