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

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

In 1600, the cosmologist Giordano Bruno, who proposed that the universe was infinite and that stars were distant suns, was burned at the stake for his heresies. —Rebecca Mead, New Yorker, 28 July 2025

At a small crossroads in southern France, in the 13th century, Dominic de Guzman, a holy man, recognized the necessity for sanctuary for women who rejected heresy and were in danger, according to the Dominican Sisters of Grand Rapids. —Jenna Prestininzi, Freep.com, 2 July 2025

The last Pope Leo was also known for promoting Marian devotion, confronting modernist heresy, and, like Benedict XVI, promoting the compatibility of faith with human reason. —The Editors, National Review, 8 May 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