hold up vs scaffold

hold up is not a noun while scaffold is a noun.

Word	Noun	Adjective	Verb	Adverb
hold up	No	No	Yes	No
scaffold	Yes	No	Yes	No

As verbs, scaffold is a hyponym of hold up; that is, scaffold is a word with a more specific, narrower meaning than hold up:

Other hyponyms of hold up include block, carry, chock, buoy, buoy up, pole, bracket, underpin, prop, prop up, shore, shore up, truss, brace.

hold up (noun)	scaffold (noun)
	a temporary arrangement erected around a building for convenience of workers
	a platform from which criminals are executed (hanged or beheaded)

hold up (verb)	scaffold (verb)
cause to be slowed down or delayed	provide with a scaffold for support
be the physical support of; carry the weight of
hold up something as an example; hold up one's achievements for admiration
rob at gunpoint or by means of some other threat
continue to live and avoid dying
resist or withstand wear, criticism, etc.
resist or confront with resistance