She thinks he's too bloody KY by far, and he's sick to death of being treated like an NTT - and if things get much more MM, he's going to MK5 and she's going to jolly well flounce off to HR.

Welcome to 21st-century Japan, no longer the land of harmony and politeness but a grim new world of acrimony by acronym.

If you were baffled by the opening sentence, you are in good company: most Japanese above the age of 25 have no idea what the dizzying new abbreviations in their language actually mean, and only the dimmest sense that they are being judged secretly and ridiculed by the younger generation.

To make matters many times worse - and with the socially critical bonenkai year-end office party season looming - the 46 most common new acronyms have been published as a series of “yellow cards” to be waved in the faces of victims.

Accordingly, someone who hogs the stage at karaoke might suddenly find himself confronted by a flurry of cards bearing the letters “MB” - maiku ga betobeto, or “sticky microphone”.

The cards, produced by one of Japan's leading toy companies, could cause havoc as their true meanings gradually filter into the public consciousness. The surging use of acronyms, sociologists and language experts say, has created a significant shift in young people's attitudes to elders, and in junior workers' attitudes to bosses. Even among acronym addicts of a similar age, the emerging lexicon allows them to trade abuse freely in a way that traditional Japanese makes rather tricky.

She thinks he is KY (kuki yomenai) because he is pathetically clueless when it comes to reading the situation; he is furious because as an NTT (nimotsu tantosha) he has had to lug her bags round the shops like a packhorse. MM (maji mukatsu) means they are both utterly disgusted with each other - MK5 (maji kireru 5 byo mae) suggests that he is going to blow his lid in five seconds, while she is sulkily going to HR (hitori ranchi), or eat on her own.

The new linguistic code, says Yasuo Kitahara, of Tsukuba University, has suddenly made it socially acceptable for Japanese to speak their minds and, disturbingly, uncorked a latent need to insult. “I'm worried about this new form of words, because when they use them, people don't hesitate to say things they couldn't possibly say in normal circumstances in everyday Japanese,” Professor Kitahara said. “I'm scared this could develop into a form of violence through speech.”

Perhaps most dreadful of all would be the husband hearing himself called an ATM by his wife - “ahona teishu mo iranai”, or “the idiot man I don't need in my life anymore”.

Short and not so sweet

AB Amai mono wa betsubara - the kind of woman who has a separate stomach for puddings

GM Gyudon no hou ga mashi - even gyudon (very cheap fast food) is better than this muck

FK Fande koi - someone who trowels on the make-up

ND Ningen to shite douyo - what the hell kind of person is this?

NTT Nimotsu tantosha - a packhorse for a girlfriend's shopping trips

OBM Okubyoumono - a man too chicken to ask a girl on a date

DD Daredemo daisuki - the kind of person who falls for anyone

NS Noryoku yori seikaku - someone promoted way beyond his competence

Times Recommends

• Rio Tinto four held as China prepares case
• Diplomats must keep heads down and trousers up
• When in Rome should one make like Berlusconi?