ascent vs upthrust

ascent and upthrust both are nouns.

Word	Noun	Adjective	Verb	Adverb
ascent	Yes	No	No	No
upthrust	Yes	No	No	No

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

ascent: a movement upward; rise above the ground
upthrust: (geology) a rise of land to a higher elevation (as in the process of mountain building)

ascent (noun)	upthrust (noun)
the act of changing location in an upward direction	(geology) a rise of land to a higher elevation (as in the process of mountain building)
a movement upward; rise above the ground
an upward slope or grade (as in a road)