propping up vs shoring

propping up and shoring both are nouns.

Word	Noun	Adjective	Verb	Adverb
propping up	Yes	No	No	No
shoring	Yes	No	No	No

As nouns, propping up and shoring are synonyms defined as:

Other synonyms of propping up include shoring up.

propping up (noun)	shoring (noun)
the act of propping up with shores	the act of propping up with shores
	a beam or timber that is propped against a structure to provide support