upright vs unsloped

upright is a noun but unsloped is not a noun.

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

As adjectives, upright and unsloped are synonyms defined as:

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

upright (adjective)	unsloped (adjective)
upright in position or posture	in a vertical position; not sloping
of moral excellence
in a vertical position; not sloping