heresy

American  

[her-uh-see] / ˈhɛr ə si /

noun

plural

heresies

1. opinion or doctrine at variance with the orthodox or accepted doctrine, especially of a church or religious system.

2. the maintaining of such an opinion or doctrine.

3. Roman Catholic Church. the willful and persistent rejection of any article of faith by a baptized member of the church.

4. any belief or theory that is strongly at variance with established beliefs, customs, etc.

   Synonyms:

   dissension, iconoclasm, dissent

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heresy British  

/ ˈhɛrəsɪ /

noun

1. 1. an opinion or doctrine contrary to the orthodox tenets of a religious body or church

   2. the act of maintaining such an opinion or doctrine

2. any opinion or belief that is or is thought to be contrary to official or established theory

3. belief in or adherence to unorthodox opinion

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heresy Cultural  

1. A belief or teaching considered unacceptable by a religious group. (See heretic.)

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Other Word Forms

• superheresy noun

Etymology

Origin of heresy

First recorded in 1175–1225; Middle English heresie, from Old French eresie, from Latin haeresis “school of thought, sect,” from Greek haíresis, literally, “act of choosing,” derivative of haireîn “to choose”

Explanation

A heresy is a belief that doesn't agree with the official tenets of a particular religion; heresy is the maintaining of such contrary beliefs. Heresy can be used figuratively: to disagree with the school committee's decisions is considered pure heresy by the faculty. You'll often come across this word in a religious context — the Latin root haeresis, "school of thought or sect," was used by Christian writers to mean "unorthodox sect or belief." This comes from the Greek hairesis, "a taking or choosing," from hairein, "to choose." A person who chooses to believe in heresies is called a heretic.

Example Sentences

For most of its 50-year history, this would have been heresy at Apple.

From The Wall Street Journal • Apr. 3, 2026

Most of the unhappy denizens of Dante’s imagined hell are being eternally tormented for specific moral crimes in categories covering lust, gluttony, greed, anger, heresy, violence, fraud and treachery.

From Salon • Mar. 8, 2026

I realize this is heresy, but I think it’s important to acknowledge the irreducible strangeness of the drama.

From Los Angeles Times • Nov. 4, 2024

But his suggestion that animals think and feel was seen as scientific heresy among many, if not most animal behaviour experts.

From BBC • Jun. 15, 2024

The work was titled Le Monde, ou Traité de la Lumière, and it was on the verge of being published when news of Galileo’s trial and conviction for heresy reached Holland.

From "The Scientists" by John Gribbin

Related Words

• blasphemy
• fallacy