gimcrack vs flashy

gimcrack is a noun but flashy is not a noun.

Word	Noun	Adjective	Verb	Adverb
gimcrack	Yes	Yes	No	No
flashy	No	Yes	No	No

As adjectives, gimcrack and flashy are synonyms defined as:

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

gimcrack (noun)	flashy (noun)
ornamental objects of no great value

gimcrack (adjective)	flashy (adjective)
tastelessly showy	(used especially of clothes) marked by conspicuous display
	tastelessly showy