"Gibson's second apology followed complaints from one prominent Jewish group, the Anti-Defamation League, that his first mea culpa, issued on Saturday, failed to get "to the essence of his bigotry and anti-Semitism".
From the AHD:
Noun: One who is strongly partial to one's own group, religion, race, or politics and is intolerant of those who differ.
Etymology: French, from Old French.
Word history: Bigots may have more in common with God than one might think. Legend has it that Rollo, the first duke of Normandy, refused to kiss the foot of the French king Charles III, uttering the phrase bi got, his borrowing of the assumed Old English equivalent of our expression by God. Although this story is almost surely apocryphal, it is true that bigot was used by the French as a term of abuse for the Normans, but not in a religious sense. Later, however, the word, or very possibly a homonym, was used abusively in French for the Beguines, members of a Roman Catholic lay sisterhood. From the 15th century on Old French bigot meant “an excessively devoted or hypocritical person.” Bigot is first recorded in English in 1598 with the sense “a superstitious hypocrite.”
From the OED
BIGOT: 1598, from M.Fr. bigot, from O.Fr., supposedly a derogatory name for Normans, the old theory (not universally accepted) being that it springs from their frequent use of O.E. oath bi God. Plausible, since the Eng. were known as goddamns in Joan of Arc's France, and during World War I Americans serving in France were said to be known as les sommobiches (see also son of a bitch). But the earliest Fr. use of the word (12c.) is as the name of a people apparently in southern Gaul. The earliest Eng. sense is of "religious hypocrite," especially a female one, and may be influenced by beguine. Sense extended 1687 to other than religious opinions.
I also looked up 'bigot' in the Oxford Dictionary of English Etymology.
[...]F. bigot (XV), of unkn. origin. Found (XII) as the proper name of a people of S. France, whence it has been referred by some to medL. Visigothi (the Visigoths of the region were Arians); it is used in Wace's 'Roman du Rou' (XII) as an abusive term by the French to Normans, and it became a Norman family name. The gap between these early references and the much later use of the word as a comon noun has not been bridged.[...]