rub vs rosin

rub and rosin both are nouns.

Word	Noun	Adjective	Verb	Adverb
rub	Yes	No	Yes	No
rosin	Yes	No	Yes	No

As verbs, rosin is a hyponym of rub; that is, rosin is a word with a more specific, narrower meaning than rub:

rub (noun)	rosin (noun)
the act of rubbing or wiping	any of a class of solid or semisolid viscous substances obtained either as exudations from certain plants or prepared by polymerization of simple molecules
an unforeseen obstacle

rub (verb)	rosin (verb)
move over something with pressure	rub rosin onto
cause friction
scrape or rub as if to relieve itching