Elon Musk condemned the words “cis” and “cisgender” as “slurs” on Twitter after a user complained about receiving harassing messages from “trans activists” calling him “cissy.”

“The words ‘cis’ or ‘cisgender’ are considered slurs on this platform,” Musk tweeted on Wednesday. “Repeated, targeted harassment against any account will cause the harassing accounts to receive, at minimum, temporary suspensions.”

The censure was in response to a tweet by conservative commentator James Esses.

“Yesterday, after posting a Tweet saying that I reject the word ‘cis’ and don’t wish to be called it, I receive a slew of messages from trans activists calling me ‘cissy’ and telling me that I am ‘cis’ ‘whether or not I like it,’” Esses tweeted.

Responses to the thread contained a slew of differing opinions — with some users celebrating Musk’s declaration and others asking how “cis” could be a slur to still others calling the move “extreme.”

“Cisgender” is a term that describes a person who identifies with the sex he or she was assigned at birth.

One user pointed out the term’s origin — from German sexologist Volkmar Sigusch, who coined the word in 1991 in a book about transgenders and penned: “If there are transsexuals, logically there must be cissexuals. One is not to be thought without the other at all. I have allowed myself to introduce the terms cissexualism, cissexuals, cisgender….”

Musk tweeted in response: “Yup, the contemptible creep that manufactured the term ‘cis’ has serious problems. Ignore him.”

Another user asked: “If that’s a slur why don’t you ban the use of the N-word on here and make it fair for everyone and just eliminate all slurs?”

Twitter’s policy on hateful conduct does not list terms that the platform considers slurs, though it clearly condemns words, “tropes or other content that intends to degrade or reinforce negative or harmful stereotypes.”

It’s unclear whether banning “cis” and “cisgender” will be upheld, and Musk has previously faced controversy over snap decisions allegedly based on personal vendettas. Last year, he was accused of firing employees who publicly and privately criticized him — both at Twitter and at his space exploration company SpaceX.

Musk has also been criticized for allegedly suppressing the visibility of tweets and direct messages containing words like “trans,” “transgender,” or “intersex.”

Twitter has been slammed for its lack of censorship since Musk bought the platform for $44 billion in October.

Just days after Musk took over the social media site, the average number of tweets containing a racial slur used to attack black people rose to over 26,200 — triple the number from the year prior, according to a study conducted by the Center for Countering Digital Hate.

Some experts, however, attributed the spike to anti-Musk trolls looking to wreak havoc on the site.

A chart released by the researchers also showed that the last time Twitter usage of the racial slur spiked was in April, the month Musk announced he planned to acquire the social media platform.

Most recently, civil rights attorney and Harvard Law School clinical instructor Alejandra Caraballo blasted Twitter for failing to moderate neo-Nazi propaganda.

Caraballo found extensive results appeared when she searched “Europa: The Last Battle” for research purposes. The film is a 2017 propaganda movie that relies on anti-Semitic themes that blame Jewish people for causing both world wars as part of a scheme to create the nation of Israel.

Caraballo said she saw clips of the movie being uploaded to Twitter.

Meanwhile, the 52-year-old Musk has a transgender child. Vivian Wilson, formerly known as Xavier Musk, was born in 2004 to the billionaire and Justine Wilson, who were married from 2000 to 2008.

At age 18, Vivian announced her decision to change her gender and famous surname in order to lose any association with the Tesla and SpaceX founder.