What is another word for bitter-ender?
Pronunciation: [bˈɪtəɹˈɛndə] (IPA) 
Bitter-ender is a term that refers to someone who holds on to a belief, idea, or cause with excessive fervor or stubbornness, even in the face of overwhelming opposition or evidence to the contrary. Some synonyms for this term include zealot, die-hard, fanatic, true believer, and dogmatist. Each of these words connotes a person who is deeply committed to their cause and unwilling to compromise or back down, even when it may be in their best interest to do so. While these individuals can be passionate and dedicated, their inflexibility can also be frustrating and counterproductive in certain contexts.
