upright vs semi-erect

upright is a noun but semi-erect is not a noun.

Word	Noun	Adjective	Verb	Adverb
upright	Yes	Yes	No	No
semi-erect	No	Yes	No	No

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

upright (adjective)	semi-erect (adjective)
upright in position or posture	of plants that are partly erect
of moral excellence
in a vertical position; not sloping