Newton vs Sir Isaac Newton

Newton and Sir Isaac Newton both are nouns.

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

As nouns, Newton and Sir Isaac Newton are synonyms defined as:

Newton and Sir Isaac Newton: English mathematician and physicist; remembered for developing the calculus and for his law of gravitation and his three laws of motion (1642-1726)

Other synonyms of Newton include Isaac Newton.

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