garish vs gaudy

garish is not a noun while gaudy is a noun.

Word	Noun	Adjective	Verb	Adverb
garish	No	Yes	No	No
gaudy	Yes	Yes	No	No

As adjectives, garish and gaudy are synonyms defined as:

Other synonyms of garish include brassy, cheap, flash, flashy, gimcrack, loud, meretricious, tacky, tatty, tawdry, trashy.

garish (noun)	gaudy (noun)
	(Britain) a celebratory reunion feast or entertainment held at a college

garish (adjective)	gaudy (adjective)
tastelessly showy	(used especially of clothes) marked by conspicuous display
	tastelessly showy