The Hairy Man of Genesis is a reference to Esau, the twin brother of Jacob in the Bible. Esau was born with a full head of hair, which earned him the nickname 'Hairy Man of Genesis'. He was also known as Edom, which is the four-letter answer to the crossword puzzle. Esau was the firstborn son of Isaac and Rebekah, and was favored by his father. He was a skilled hunter and outdoorsman, and was known for his strength and courage.