physicist vs Sir Isaac Newton

physicist and Sir Isaac Newton both are nouns.

Word	Noun	Adjective	Verb	Adverb
physicist	Yes	No	No	No
Sir Isaac Newton	Yes	No	No	No

physicist (noun)	Sir Isaac Newton (noun)
a scientist trained in physics	English mathematician and physicist; remembered for developing the calculus and for his law of gravitation and his three laws of motion (1642-1726)