heresy

noun

her·​e·​sy ˈher-ə-sē 

ˈhe-rə-

plural heresies

1

a

: adherence to a religious opinion contrary to church dogma (see dogma sense 2)

They were accused of heresy.

b

: denial of a revealed truth by a baptized member of the Roman Catholic Church

c

: an opinion or doctrine contrary to church dogma

2

a

: dissent or deviation from a dominant theory, opinion, or practice

To disagree with the party leadership was heresy.

b

: an opinion, doctrine, or practice contrary to the truth or to generally accepted beliefs or standards

our democratic heresy which holds that … truth is to be found by majority vote

—M. W. Straight

Synonyms

• dissent
• heterodoxy

Examples of heresy in a Sentence

They were accused of heresy.

He was preaching dangerous heresies.

Recent Examples on the Web

In the value-investing, human discretion driven ethos of PIMCO this was heresy. —Vineer Bhansali, Forbes.com, 9 Sep. 2025

All have historical roots, many once considered and debated, just to be cast aside during the Oslo years, when the two-state solution—whose roots were shallower—ruled supreme, became the lingua franca, and all else was deemed heresy. —Hussein Agha, New Yorker, 22 Aug. 2025

His writings were condemned by the church as heresy but found a fan centuries later in Martin Heidegger, which makes sense. —Jon Raymond august 5, Literary Hub, 5 Aug. 2025

The company descended into a form of professional wrestling madness as storylines no longer made sense, with the curtain frequently pulled back to expose pro wrestling in a way that was heresy to many longtime fans. —Kyle Feldscher, CNN Money, 24 July 2025

Word History

Etymology

Middle English heresie, borrowed from Anglo-French, borrowed (with assimilation to the suffix -ie -y entry 2) from Late Latin haeresis, heresis "school (of philosophy or theology), sect, belief contrary to church dogma," borrowed from Greek haíresis "act of taking, choice, course of action or thought, system of principles, sect, faction," from haireîn "to take, grasp, (middle voice) obtain, choose, prefer" (of obscure origin) + -sis -sis

First Known Use

13th century, in the meaning defined at sense 1a

Kids Definition

heresy

noun

her·​e·​sy ˈher-ə-sē 

plural heresies

1

: religious opinion that is opposed to the doctrines of a church

2

: opinion that is opposed to a generally accepted belief