Most of us have heard the phrase before — that’s just heresy. It’s often used to dismiss false statements or statements that have yet to be proven. It’s a word that’s used often. British current affairs magazine spiked used the word while describing politicians’ refusal to criticize the National Health Service in “The Heresy of Criticising The NHS”. After the State of the Union address, Vanity Fair referred to President Trump’s immigration statements as heresy. However, use of the word isn’t limited to political matters. A recent AV Club article called the Shadow of the Colossus remake heresy. But heresy hasn’t always served as a universal term for combatting falsehoods.

Merriam-Webster offers two definitions. The second is the meaning we’re most familiar with — “a dissent or deviation from a dominant theory, opinion, or practice”. However, the first remains true to the word’s origins — “adherence to a religious opinion contrary to church dogma; denial of a revealed truth by a baptized member of the Roman Catholic Church”.

Heresy first surfaced in 1200 as a derivative of the old French word heresie, and by extension the Latin and Greek words haeresis and hairesis, respectively. It was used as a way to define private opinions that differed from the teachings of the church.

There was a very hostile response to heresy; it wasn’t a lighthearted term. Publicly touting information that didn’t align with the church was treated seriously. Britannica cites the first disapprovals of heresy showing up in the New Testament. Back then, dissenting opinions took shape as opposing ideologies. Adoptionism, Gnosticism, and Montanism were just a few of the philosophies that countered Christianity.

In the 12th and 13th centuries, the church dealt with heretics (those who spread heresy) by excommunicating them. The punishment’s severity intensified with time, and, if heretics refused to change their ideology, they were punished by local civil authorities, often by execution.

Heresy was a grave matter. However, the 16th century Reformation took place and saw some approved changes to the ways many worshipped. By the 20th century, the church relaxed its approach as more formal sects of Christianity started to form.

Today, the Catholic Church still has rules on the books about heresy and actively issues doctrines about modern day heretics. For example, the Congregation for the Doctrine of the Faith issued a notice against Jon Sobrino of El Salvador in 2007. He was accused of spreading beliefs that denied many of the foundational Catholic teachings and was viewed as dangerous. However, punishment for heresy does not result in any legal action today.

Despite its continued use in Catholicism, heresy has become a colloquial term. Perhaps this is due to the connection some historians have made between heretics and witches. History Extra interviewed Bob Moore of the University of Nottingham. During the interview, he cited the fear of witches that prevailed from the 15th-18th centuries and suggested the fear of heretics was just as feverish. In this light, heresy could be seen as more of a social issue than a religious one.

Thus, today’s use revolves around discounting opinions that aren’t rooted in fact. Heresy is even a cheeky apparel brand. But it seems its religious application is a thing of the past.