gaudiness vs loudness

gaudiness and loudness both are nouns.

Word	Noun	Adjective	Verb	Adverb
gaudiness	Yes	No	No	No
loudness	Yes	No	No	No

As nouns, gaudiness and loudness are synonyms defined as:

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

gaudiness (noun)	loudness (noun)
strident color or excessive ornamentation	the magnitude of sound (usually in a specified direction)
tasteless showiness	tasteless showiness