amass vs roll up

amass and roll up both are verbs.

Word	Noun	Adjective	Verb	Adverb
amass	No	No	Yes	No
roll up	No	No	Yes	No

As verbs, amass and roll up are synonyms defined as:

Other synonyms of amass include accumulate, collect, compile, hoard, pile up.

amass (verb)	roll up (verb)
increase in amount by collecting or gathering	form a cylinder by rolling
get or gather together	form into a cylinder by rolling
	show certain properties when being rolled
	make into a bundle
	close (a car window) by causing it to move up, as with a handle
	arrive in a vehicle:
	get or gather together