Dictionary.com
Thesaurus.com
Synonyms

fanaticism

American  
[fuh-nat-uh-sahyz-uhm] / fəˈnæt əˌsaɪz əm /

noun

  1. fanatical character, spirit, or conduct.


fanaticism British  
/ fəˈnætɪˌsɪzəm /

noun

  1. wildly excessive or irrational devotion, dedication, or enthusiasm

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What does fanaticism mean? Fanaticism is an extreme and often unquestioning enthusiasm, devotion, or zeal for something, such as a religion, political stance, or cause. It can also refer to behavior motivated by such enthusiasm or devotion. A person who engages in fanaticism can be called a fanatic, and they or their behavior or beliefs can be described as fanatical. Sometimes, fanatic is used negatively to imply that someone takes such devotion too far, as in They’re considered religious fanatics due to their extreme practices. Close synonyms are extremist, radical, and zealot. Other times, fanatic is not used negatively but instead simply refers to someone who is extreme in their devotion or enthusiasm for an interest or hobby. For example, calling someone a sports fanatic means they’re an extremely enthusiastic fan of sports. In fact, the word fan is a shortening of fanatic. Fanaticism can be used in reference to either kind of fanatic. Example: We dismiss it as fanaticism, but this belief system may be more widespread than we think.

Etymology

Origin of fanaticism

First recorded in 1705–15; fanatic + -ism

Explanation

Fanaticism occurs when someone is unwilling or unable to accept a differing point of view. You can use the word to describe the endless war between fans of the Boston Red Sox and the New York Yankees. Fanaticism come from the Latin word fanaticus, a word with a meaning that includes the word mad — in both senses. If you're mad, you might be angry — or you might be insane. Fanaticism involves both kinds of madness. Anger at those who disagree with you, taken so far that there's a desire to stop or even harm the dissenters? That's madness — and also fanaticism.

Keep Reading on Vocabulary.com

Vocabulary lists containing fanaticism

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Participants completed the Football Supporters Fanaticism Scale, a 13-item questionnaire measuring two aspects of fandom: "Inclination to Violence" and "Sense of Belongingness."

From Science Daily • Nov. 11, 2025

Linguist Amanda Montell, author of Cultish: The Language of Fanaticism, explains people can "erect a cult around anything, as long as you can inject it with fear and an 'us-versus-them' mentality".

From BBC • Aug. 1, 2025

Among the provisions: Legislation designed to speed trials in terrorism-related cases and the formation of a Supreme Council to Combat Terrorism and Fanaticism, which gave some Egyptians hope of added security.

From Los Angeles Times • Apr. 15, 2017

Fanaticism always seems foolish until it locks you up.

From The New Yorker • Jan. 8, 2017

Fanaticism in war, of the type that drove recorded Christian and Islamic conquests, was probably unknown on Earth until chiefdoms and especially states emerged within the last 6,000 years.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

Vocabulary.com logo
by dictionary.com

Look it up. Learn it forever.

Remember "fanaticism" for good with VocabTrainer. Expand your vocabulary effortlessly with personalized learning tools that adapt to your goals.

Take me to Vocabulary.com