1. stubborn and complete intolerance of any creed, belief, or opinion that differs from one’s own.
2. the actions, beliefs, prejudices, etc., of a bigot, i.e. an intolerant and prejudiced person, i.e. the state of mind of a bigot - someone who, as a result of their prejudices, treats or views other people with fear, distrust, hatred, contempt, or intolerance on the basis of a person’s opinion, ethnicity, race, religion, national origin, gender, gender identity, sexual orientation, disability, socioeconomic status, or other characteristics.
Etymology: from French bigoterie, from Old French -name applied contemptuously to the Normans by the French, of obscure origin.
I know a lot of bigots who probably don’t realize they are one.