passkey vs passe-partout

passkey and passe-partout both are nouns.

Word	Noun	Adjective	Verb	Adverb
passkey	Yes	No	No	No
passe-partout	Yes	No	No	No

As nouns, passkey and passe-partout are synonyms defined as:

Other synonyms of passkey include master, master key.

passkey (noun)	passe-partout (noun)
key that secures entrance everywhere	key that secures entrance everywhere
	a mounting for a picture using gummed tape