brashness vs flashiness

brashness and flashiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
brashness	Yes	No	No	No
flashiness	Yes	No	No	No

As nouns, brashness and flashiness are synonyms defined as:

Other synonyms of brashness include garishness, gaudiness, glitz, loudness, meretriciousness, tawdriness.

brashness (noun)	flashiness (noun)
the trait of being rash and hasty	tasteless showiness
tasteless showiness