Emily Dickinson Lexicon

BIG'OT, n. [Fr. bigot, and cagot, a bigot or hypocrite; Arm. bigod. In Italian, bacchettone is a hypocrite. In Spanish, bigote is a whisker; hombre de bigote, a man of spirit; tener bigotes, to be firm or undaunted. If the French cagot is connected with bigot, the first syllable in both is a prefix. But I am not able to ascertain the real origin and primary sense of the word. The etymologies I have seen are not satisfactory.]

1. A person who is obstinately and unreasonably wedded to a particular religious creed, opinion, practice, or ritual. The word is sometimes used in an enlarged sense, for a person who is illiberally attached to any opinion, or system of belief; as a bigot to the Mohammedan religion; a bigot to a form of government.
2. A Venetian liquid measure containing the fourth part of the amphor, or half the boot. – Encyc.