“That’s my name, don’t wear it out.” So went a popular epigram from my primary school days, demonstrating that even eight-year-olds have an inherent sense of the dangers of semantic erosion: say a word, any word, 20 times in a row and watch as its meaning evaporates, leaving an empty shell.

When a small band of pro-Brexit protesters, cosplaying as French yellow vests, interrupted a BBC interview with Conservative MP Anna Soubry to call her a “Nazi” over her support for a second EU referendum, they were operating at the avant-garde of a semantic inversion that’s been a long time in the forging, one facilitated by decades of overuse and casual misapplication.

Coming from James Goddard, the far-right Islamophobic leader and a supporter of the EDL’s Tommy Robinson, it may have seemed a classic if unremarkable case of wolf crying wolf, yet understanding what’s become of the word “Nazi” is helpful to understanding our current political discourse – and a dilemma now faced by the left.

Once a proper noun with a singular, universally understood referent, “Nazi” has undergone a semantic broadening in recent decades: first there were grammar Nazis, then soup Nazis, then Zionazis. A Nazi was no longer someone who committed genocide but a person who withheld bread rolls or pointed out grocers’ commas. Meanwhile, its overuse as a byword for evil led to a semantic softening. An internet axiom known as Godwin’s Law states that, as an online comment thread develops, the probability of someone being compared to a Nazi or Hitler approaches one. In recent years, as the gap between on and offline interactions shrinks and URL becomes IRL, “Nazi” has worked its way back into mainstream political discussion.

Anna Soubry stops BBC interview as Brexit protesters call her a Nazi

In many ways, the return of “Nazi” to frontline politics ought to come as a welcome intervention; with far-right parties making gains across Europe, Brazil electing a fascist leader, Donald Trump shutting down the US government to build a border wall to keep out Mexican ”rapists” and discussion around Brexit continuing to circle the drain of ethno-nationalism, what better time to remind ourselves of where these things can ultimately lead?

But the word Nazi, in its current usage, is less a warning from history than a reflection of our fractured present. At times, its meaning can seem slippery, even quantum; at others it’s perfectly clear, and recalls Jeremy from Peep Show’s claim that justice is just another word for “what I wanted to happen”. A Nazi, in 2019, is someone you disagree with.

And no one knows this better or has capitalised on it more shrewdly than the far-right. It takes a certain chutzpah to try to ban a word as a slur, as if labelling fascism is the same as fascism, while also claiming that the true Nazis are the students who refuse a platform to hatemongers and the MPs wary of our jingoist tendencies. But it’s typical of a moral equivalence (and cognitive dissonance) the far-right increasingly relies on.

The genius and danger of this is that it appeals to traditional left-wing values of free speech and tolerance – and the left, as well as the media and the police, have indulged a resurgent far-right on the grounds that denying them protest permits and seats on Newsnight is the same as trampling their rights.

Really, though, this isn’t such an unsolvable paradox: tolerance of intolerance is not tolerance, it’s a failure of both judgement and conviction. All of us may be guilty of exaggerating views we disagree with and demonising those who hold them, but that doesn’t mean we can lower our guard when there are those among us who mean others harm.

Matt Greene is the author of ‘Ostrich’. His forthcoming book, ‘Max & Me’, deals with contemporary antisemitism​ and the changing face of Holocaust denial