upright vs passant

upright is a noun but passant is not a noun.

Word	Noun	Adjective	Verb	Adverb
upright	Yes	Yes	No	No
passant	No	Yes	No	No

upright (noun)	passant (noun)
a piano with a vertical sounding board
a vertical structural member as a post or stake

upright (adjective)	passant (adjective)
upright in position or posture	in walking position with right foreleg raised
of moral excellence
in a vertical position; not sloping