root on vs urge

root on is not a noun while urge is a noun.

Word	Noun	Adjective	Verb	Adverb
root on	No	No	Yes	No
urge	Yes	No	Yes	No

As verbs, root on and urge are synonyms defined as:

Other synonyms of root on include barrack, cheer, exhort, inspire, pep up, urge on.

root on (noun)	urge (noun)
	a strong restless desire
	an instinctive motive

root on (verb)	urge (verb)
spur on or encourage especially by cheers and shouts	force or impel in an indicated direction
	spur on or encourage especially by cheers and shouts
	push for something