upright vs scantling

upright and scantling both are nouns.

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

As nouns, scantling is a hyponym of upright; that is, scantling is a word with a more specific, narrower meaning than upright:

Other hyponyms of upright include column, pillar, jamb, post, stud, scape, shaft, stile.

upright (noun)	scantling (noun)
a piano with a vertical sounding board	an upright in house framing
a vertical structural member as a post or stake

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