passe vs old-hat

passe and old-hat both are adjectives.

Word	Noun	Adjective	Verb	Adverb
passe	No	Yes	No	No
old-hat	No	Yes	No	No

As adjectives, passe and old-hat are synonyms defined as:

Other synonyms of passe include antique, demode, ex, old-fashioned, outmoded, passee.

passe (adjective)	old-hat (adjective)
out of fashion	out of fashion
	repeated too often; overfamiliar through overuse