___ Newton, physicist, mathematician, alchemist, d. 1727 (5)
I believe the answer is:
isaac
(Other definitions for isaac that I've seen before include "Father to Jacob and Esau" , "Son of Abraham, offered as a sacrifice to God" , "man whose sons bargained over 3 [A MESS OF POTAGE]" , "Boy's name" , "___ Newton, English physicist, d. 1727" .)