On November 11, Thomas Middleditch and Kumail Nanjiani, stars of the hit HBO comedy series Silicon Valley, were approached at a Los Angeles bar by two young white men—self-proclaimed fans who told the TV stars they were “wrong about Trump.”

Both actors had tweeted their profound disappoint with Trump’s election victory in the days since the election. Americans had condoned racism, Middleditch wrote. Nanjiani, the son of Pakistani immigrants, expressed grave concern for his and his family’s safety.

Nanjiani tried to defuse the situation by saying he and Middleditch didn’t want to discuss politics. But the Trump supporter persisted, getting in Middleditch’s face and calling them both “cucks.” (Security kicked him out shortly thereafter.)

The incident left the actors stunned and bewildered, both by the intensity of the exchange and the man’s use of cuck, a word that was absent from the American vernacular until just two years ago, but went mainstream this election season.

The next day, Middleditch confirmed what many internet users already knew: “cuck” is the right’s political epithet du jour for liberals.

Cuck is short for “cuckold,” a derogatory term for a man whose wife or girlfriend has sex with another man. It first appeared in writing in the Middle English poem “The Owl and the Nightingale,” written sometime between 1189 and 1296.

The poem consists of two birds trading insults with each other — and could have served as unofficial inspiration for this year’s presidential debates. Early in the poem, the nightingale calls the owl a “nasty creature.” The owl answers: “Do you think that I can’t sing just because I can’t twitter?”

In one section, the nightingale and owl debate who’s at fault when a woman cheats on her husband. The nightingale disapproves of a wife cheating, but says it indicates her husband has “little to offer in the bed and at the table.” The owl responds that cheating is proper revenge for the mistreatment women suffer from men. “She can be ill-treated so often that she resolves to satisfy her own needs. God knows, she can’t help it if she makes him a cuckold.”

“Cuckold” derives from the French term for the cuckoo, a bird that lays eggs in other bird’s nests, leaving others to raise her offspring. The author of the poem is unknown, but the term he used became a favorite of William Shakespeare’s. “Cuckold” appears more than two dozen times in Shakespeare’s plays, including both Hamlet and Othello. “Who would not make her husband a cuckold, to make him a monarch?” Emilia asks Desdemona in Othello’s third act. (Translation: “I’d sleep with another man if it meant my husband could be king.”)

The word’s popularity waned over the next several centuries, according to Michael Adams, a linguistics professor at Indiana University who researches slang and profanity. It made a comeback in the mid-2000s within BDSM communities, who used the term to describe men getting off on the humiliation of having their wives and girlfriends fucked by stronger, more virile men. But it wasn’t until GamerGate that cuckold, and its derivatives “cucked” and “cuck,” entered the mainstream internet lexicon.

In August 2014, Eron Gjoni published a 9,000-word screed about his ex-girlfriend Zoe Quinn, an independent videogame developer he accused of sleeping with gaming journalists. Gamers took the story as proof of rampant corruption in the industry and harassed Quinn and other women in gaming, coordinating mass boycotts against the publications supposedly in league with them.

GamerGate, as it came to be known, was one of the more odious online movements in recent memory and bears responsibility for popularizing “cuck” as an online epithet. Shortly after the blog post went viral, members of the online message board community 4chan took to calling Gjoni a “beta cuck.”

Shortening the term to rhyme with “fuck” made a more visceral insult, Adams says. And using the term alongside “beta” — as in, the opposite of an alpha male — reinforced its meaning as a man who’s timid, deferential and lacking in toughness and conviction. That said, cuck isn’t the same as “pussy.”

“‘Pussy’ feminizes a man,” Adams says. “‘Cuck’ stays in the masculine sphere, but it says you’re an unnatural man, someone who can’t stand for himself. … A cuck isn’t a doofus who doesn’t ‘get it.’ He’s inadequate, unable to hold on to what’s his.”

Cuck spread to other sections of 4chan after GamerGate. Comedian Louis C.K. earned the title “Louis Cuck King” for talking about white privilege in his standup routines, and the term started appearing on the site’s politics and television and film message boards. “It’s replaced the once-popular insult of ‘faggot’ that gets thrown out casually,” writes one 4chan user.

The term was entering more mainstream internet channels, particularly Twitter, by early 2015. In January 2014, “cuck” appeared in about 1,000 tweets per day, according to social media analytics firm Crimson Hexagon. By January 2015, it was being tweeted upwards of 5,500 times daily.

But the term exploded in popularity in July 2015, a month after Trump announced his presidential run in a speech calling Mexicans “rapists.” Trump supporters immediately co-opted cuck as a derogatory term for political opponents. The term was being tweeted 13,000 times a day by the end of July.

Cuck was especially trendy on r/The_Donald, a subreddit for people who supported the candidate. Whereas cuck fetishists obtain satisfaction from watching other men have sex with their wives, political cucks like “watching the interests of others surpass the interests of their country,” one of the subreddit moderators explains. Trumpers want to make America great again. Cucks don’t.

Soon, the term was embraced by Trump supporters at large, including right-wing firebrand Milo Yiannopoulos. You’re a cuck if your girlfriend is on birth control, he wrote last December. Conservative leaders were cucks for meeting with Mark Zuckerberg this May to address concerns about Facebook Trending’s liberal bias. And Republicans who denounced the alt-right were cucks, in Yiannopoulos’ estimation.

Cuck’s usage on Twitter steadily increased during the beginning of this year and started gaining traction outside of political speech. Cuck replaced “butthurt” as the “pejorative of choice” for commenters on sports websites, Deadspin writer Drew Magary wrote in April. The trend dovetailed with a similar increase in searches for cuckold porn, according to porn aggregator Pornhub.

Crimson Hexagon data show “cuck” hit a fever pitch just before the election, with the word being tweeted 63,000 times on November 6. Fifteen percent of those tweets also included “Trump.”

The term is now also being used as a rebuke of what many on the right perceive as PC liberalism run amok. “When did the world get so liberally cucked?” asks one thread on r/the_donald. PC culture has “deluded” people into being ashamed of their personal accomplishments, says r/the_donald moderator. “You got a good job? White privilege, male privilege, straight privilege. … The need to feel someone else is holding you down, that’s cuck-y.”

But just as some Clinton supporters reclaimed Trump’s “nasty woman” comment, some leftie men are attempting to reclaim cuck.

A day after being accosted in the bar, Thomas Middleditch said he was a proud cuck, and tweeted a link to an online store selling T-shirts that read “CUCK AF.”