roll up vs lump

roll up is not a noun while lump is a noun.

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

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

Other hyponyms of roll up include run up, corral, collect, pull in, come up, scrape, scrape up, scratch, chunk, bale, catch, fund, fund.

roll up (noun)	lump (noun)
	a compact mass
	a large piece of something without definite shape
	an awkward stupid person
	an abnormal protuberance or localized enlargement

roll up (verb)	lump (verb)
form a cylinder by rolling	group or chunk together in a certain order or place side by side
form into a cylinder by rolling	put together indiscriminately
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