As the United Kingdom wakes in yet another pool of fevered Brexit sweat, here are the essential things to know – and a glossary for bluffing your way through a conversation about it all

Just when you thought the USA was running away with the title of most abjectly humiliating end-of-empire flameout, Britain has surged back into contention overnight. Theresa May’s tweaked Brexit plan was voted down by the baying animals of Westminster 391 votes to 242, with 75 Conservative Party MPs rebelling against the prime minister. That meant a hard breakfast of newspaper front pages, hollering things like “mayhem”, “crisis”, “despair”, “humiliating”, “humiliating” and “humiliating”.

We’re only part-way into a week of parliamentary activity in Brexitmania Britain. After the rejection of May’s first negotiated withdrawal deal in January, and now the (very slightly) revised version, in the form of a 585-page agreement which included a transition period running to the end of 2020, there are likely to be at least two more big votes, and a bunch of possible amendments thrown into the mix.

Everyone knows it’s an unholy mess. No one knows what is going to happen. It’s a hell of a struggle even to keep up. Here’s our guide to the Brexit alphabet soup, and 11 terms, from A to Z, that will help you navigate a water-cooler conversation.

Article 50

Just less than two years ago, Theresa May invoked Article 50 of the Treaty on European Union, the legal mechanism that would take the UK out of the EU on 29 March 2019. That all followed the June 2016 referendum in which 52% of Britons voted to quit the EU. According to several high-level sources, 29 March 2019 is pretty fucking soon. Hence, the jamboree of parliamentary votes this week.

Backstop

Warning, this is important but quite technical and dull. The tl;dr for pub chat is that it’s about Ireland.

The slightly longer version: apart from the interesting decision to jettison membership of a political union that has provided an extraordinary peace after centuries of fighting each other basically all the time, another major geopolitical impact of the decision to leave the EU concerns Ireland. With the Republic of Ireland content as a member of the EU and Northern Ireland part of Brexiting Britain, what would happen there? The prospect of a hard border, with checkpoints and the rest, would imperil the hard-fought, still-delicate peace that followed the hell of the Troubles.

For that reason, the idea of a “backstop” was arrived at – a kind of insurance policy ensuring that even if no formal deal on trade and security were agreed, a frictionless border would, temporarily at least, prevail. That became very sticky, particularly over concerns that the backstop would become in practice permanent. Among the few appendices in this week’s May deal from that which was soundly rejected by MPs in January was a legally binding assurance that it would only be temporary. That went belly-up, however, when, with hours to go before Tuesday’s vote, the attorney general essentially said it didn’t change a thing.

All of this is complicated by the fact that May’s government depends for its majority on the support of the DUP, a hardline Northern Irish unionist party, and who voted against the offer on Tuesday.

David Cameron

Everyone is giving Theresa May, who croaked her way through another hellish day, plenty of shit, and goodness knows she’s not exactly excelled in her Great Unifier endeavours. But don’t forget that she was a remainer, only taking on the life-sucking task of attempting to negotiate Britain out of the European Union after public relations flak David Cameron whistled his way to the prime ministership, blithely promised a referendum to placate a smallish scrum of chuntering Europhobic Tory MPs because probably he wasn’t going to win the election anyway and if he did it would be completely unthinkable that Britain would vote to extract itself, right? Right? Not to mention Boris Johnson, the faux-fop maniac who probably pretended to back Brexit to raise his profile for a future leadership challenge and snuggled up with UKIP and Michael Gove in a campaign of obfuscation, dog-whistling and bullshit that deepened hatred, fear and distrust. Still, tally-ho!

ERG

The European Research Group is the hardline Eurosceptic group in the Conservative Party. Chaired by Jacob Rees-Mogg, a Tory who makes Boris Johnson look like an everyday human, the group has come under pressure to support the May-negotiated deal for fear that otherwise they might not get a Brexit at all, especially if parliament continues to vote against basically anything put to them and they end up with a fresh election and/or a second referendum. They’ve said any such suggestion is “bullying”.

Extension

Pundits are picking that a no-deal Brexit will this week get rejected by MPs (more on that later), with May next offering a vote for an attempt to win an extension to the fast-approaching deadline. It would require all 27 EU leaders’ support, and May has said that she’d need to be able to make the case for why an extension was needed – that is, something more than “we don’t like this deal” – but pushing out the March 29 deadline by two or three months does seem like the likeliest scenario. It may only kick the can down the road, but would have the rare effect of seeing MPs actually vote in support of something, anything.

Hard Brexit, soft Brexit, No-deal Brexit

Important basic vocabulary, this. The Brexit spectrum (Brextrum) has long been defined according the soft end, which would see the UK remain in the customs union and the single market, and a Hard Brexit, which basically means going it alone. Then there’s a “no-deal Brexit”. After they rejected May Deal 2.0, the prime minister will offer MPs a “free vote” on a no-deal Brexit, which they’ll almost certainly reject (though the likes of the ERG quite fancy it). A no-deal Brexit is the hardest of hard Brexits, meaning cutting all ties, without any transition period or accommodations. The prospect of such a thing is why a surprisingly large number of Britons have – not kidding – started stockpiling a lot of stuff.

Independent Group

A group of 11 MPs from both the Labour and Conservative parties, who have quit their old tribes. They are pretty inchoate philosophically but united by their support for the EU, which has placed a bit of pressure on their respective old homes, and by their loathing for their own leaders.

Malthouse compromise

Dropping a line or two of “ah, the Malthouse compromise” over the dinner table will mark you out as a very clear genius saddo. Named after the housing minister involved in coming up with it, the Malthouse compromise is an esoteric plan providing a “managed no-deal” by installing a transition period and solving the Irish border problem with, you know, technology. It did manage to unite different flanks of the Tory Party. The EU reportedly thinks it’s bonkers.

People’s vote

A cross-party group calling for a second referendum to approve any Brexit deal negotiated before it is implemented. The opposition Labour Party recently joined the call for another vote, albeit equivocally and fairly late in the piece, though there has been a push in recent days to pull back for the time being while the immediate dramas play out.

Snap election

A constitutional impasse with such enormous stakes does suggest a fresh election would be a good idea. That has been made more complicated since the introduction of the Fixed Terms Parliament Act, which means they go to the polls every five years unless parliament backs a fresh ballot by a vote of two thirds or no government can form after a no-confidence vote. But it still might happen. And on current polling it would return another Conservative government with the same divisions.

Zugzwang

A German word that literally means “compulsion to move”. Explains Robert Macfarlane: “A chess term for a situation where one is forced by the rules of the game to make a move, but all possible moves are disadvantageous. Sometimes yelled by opponents in an outburst of unseemly triumph.”