WordNet (r) 3.0 (2006):

Esau
    n 1: (Old Testament) the eldest son of Isaac who would have
         inherited the covenant that God made with Abraham and that
         Abraham passed on to Isaac; he traded his birthright to his
         twin brother Jacob for a mess of pottage

Easton's 1897 Bible Dictionary:

Esau
   hairy, Rebekah's first-born twin son (Gen. 25:25). The name of
   Edom, "red", was also given to him from his conduct in
   connection with the red lentil "pottage" for which he sold his
   birthright (30, 31). The circumstances connected with his birth
   foreshadowed the enmity which afterwards subsisted between the
   twin brothers and the nations they founded (25:22, 23, 26). In
   process of time Jacob, following his natural bent, became a
   shepherd; while Esau, a "son of the desert," devoted himself to
   the perilous and toilsome life of a huntsman. On a certain
   occasion, on returning from the chase, urged by the cravings of
   hunger, Esau sold his birthright to his brother, Jacob, who
   thereby obtained the covenant blessing (Gen. 27:28, 29, 36; Heb.
   12:16, 17). He afterwards tried to regain what he had so
   recklessly parted with, but was defeated in his attempts through
   the stealth of his brother (Gen. 27:4, 34, 38).

     At the age of forty years, to the great grief of his parents,
   he married (Gen. 26:34, 35) two Canaanitish maidens, Judith, the
   daughter of Beeri, and Bashemath, the daughter of Elon. When
   Jacob was sent away to Padan-aram, Esau tried to conciliate his
   parents (Gen. 28:8, 9) by marrying his cousin Mahalath, the
   daughter of Ishmael. This led him to cast in his lot with the
   Ishmaelite tribes; and driving the Horites out of Mount Seir, he
   settled in that region. After some thirty years' sojourn in
   Padan-aram Jacob returned to Canaan, and was reconciled to Esau,
   who went forth to meet him (33:4). Twenty years after this,
   Isaac their father died, when the two brothers met, probably for
   the last time, beside his grave (35:29). Esau now permanently
   left Canaan, and established himself as a powerful and wealthy
   chief in the land of Edom (q.v.).

     Long after this, when the descendants of Jacob came out of
   Egypt, the Edomites remembered the old quarrel between the
   brothers, and with fierce hatred they warred against Israel.


Hitchcock's Bible Names Dictionary (late 1800's):

Esau, he that acts or finishes