upright vs orthostatic

upright is a noun but orthostatic is not a noun.

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

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

upright (adjective)	orthostatic (adjective)
upright in position or posture	pertaining to an upright standing posture
of moral excellence
in a vertical position; not sloping