When the machines started hallucinating

The Cambridge Dictionary—an online dictionary for learners of English—has added a new meaning to its definition of ‘hallucinate’ and has picked ‘hallucinate’ as its Word of the Year for 2023. Cambridge Dictionary names ‘Hallucinate’ Word of the Year 2023 | University of Cambridge

Hallucinating ‘false information’

This year has seen a surge in interest in generative artificial intelligence (AI) tools like ChatGPT, Bard and Grok. AI tools, especially those using large language models (LLMs), have shown they can generate plausible prose, but sometimes using false, misleading or made-up ‘facts’. For example:

  • a US law firm used ChatGPT for legal research, which led to fictitious cases being cited in court.
  • in Google’s own promotional video for Bard, the AI tool claimed wrongly that the first ever picture of any exoplanet (a planet outside our solar system) was taken by the James Webb Space Telescope.  

The definition

The traditional definition of hallucinate is ‘to seem to see, hear, feel, or smell something that does not exist, usually because of a health condition or because you have taken a drug’.

The new, additional definition is:

‘When an artificial intelligence (= a computer system that has some of the qualities that the human brain has, such as the ability to produce language in a way that seems human) hallucinates, it produces false information.’


The Cambridge says that AI hallucinations are also known as confabulations.

I find it interesting that the new sense of ‘hallucinate’ is being applied to the output of a machine, rather than to the state of the machine’s presumably non-existent mind. To my way of thinking, ‘hallucinate’ is a less appropriate word for the output than ‘confabulate’.

New words, new meanings

Cambridge says its lexicographers added more than 6,000 new words, phrases and senses in 2023 to the Cambridge Dictionary’s 170,000+ English definitions. Beyond ‘hallucinate’, several additions reflect other rapid developments in AI and computing, such as:

  • Prompt engineering. In artificial intelligence, the process of designing prompts that will give the best possible results.
  • Large language model. A complex mathematical representation of language that is based on very large amounts of data and allows computers to produce language that seems similar to what a human might say.
  • GenAI. Abbreviation for generative AI: the use or study of artificial intelligences that are able to produce text, images, etc.
  • Train. In machine learning, to create or improve a computer representation of a system or process by supplying it with data.
  • Black box. A system that produces results without the user being able to see or understand how it works.


A couple of items in this surprise me:

I hadn’t see prompt engineering before. Including the definition in the dictionary is helpful because I would probably have assumed the phrase meant ‘speedy, timely engineering’, not ‘designing prompts’.  

Other signs of the times

The Cambridge press release states that there were spikes in public interest and searches on the Cambridge Dictionary website for several other words, including:

  • Implosion. (1) The act of falling towards the inside with force; (2) A situation in which something fails suddenly and completely.
    The press release says the tragic implosion of the Titan submersible led many to look up the definition.
  • Ennui. A feeling of being bored and mentally tired caused by having nothing interesting or exciting to do.
    The Cambridge press release says that ‘ennui’ was the Wordle answer on 5 June 2023.
    The press release also refers to a French robber Rédoine Faïd blaming ‘ennui’ for his helicopter jailbreak. ‘The ennui provoked the escape… My addiction to liberty has consumed me.’
    The press release doesn’t say whether he was using the French ennui word, the English word ennui or a Gallicism in English. In fact, the whole of the quotation has a Gallic feel: unEnglish use both of the definite article before ennui and of the present perfect; also, I suspect a first language speaker of English would be more likely to say ‘freedom’ rather than ‘liberty’.
  • Grifter. Someone who gets money dishonestly by tricking people.
    Public figures were controversially accused of being ‘grifters’, including Prince Harry and Megan Markle (by a Spotify executive) and Nigel Farage (by Coutts bank).
    Although I don’t think this word is common, I’m a little surprised it wasn’t already in the dictionary.
  • GOAT. Abbreviation for Greatest Of All Time: used to refer to or describe the person who has performed better than anyone else ever, especially in a sport.
    The Qatar World Cup provoked new debates about who the GOAT is in football: Lionel Messi, Cristiano Ronaldo, or one of the late greats like Pelé or Diego Maradona.

Some other additions to the Cambridge Dictionary in 2023

The press release highlights a few other additions in 2023:

  • Shadowban. An act of a social media company limiting who can see someone’s posts, usually without the person who has published them knowing.
  • Vibe check. An act of finding out how someone is feeling or how they make you feel, or what the mood in a particular place or situation is.
  • Water neutral. (Of a building development, business, etc) not using more water than was used in an area before it was built or established, or not removing more water than it replaces.
  • Pick up what someone is putting down (US). to understand what someone means by their words, music, etc.
  • Affrilachian. An African American who comes from or lives in the region of Appalachia in the eastern United States.
  • Range anxiety. The fear that an electric vehicle will not have enough battery charge to take you where you want to go to.
  • UBI. Abbreviation for universal basic income: an amount of money that is given regularly to everyone or to every adult in a society by a government or other organisation and that is the same for everyone.

Of these:

  • I’ve seen range anxiety a lot recently.
  • Water neutral is obviously more topical now, but the combination of words is transparent, so I’m not sure a dictionary needs to cover it.
  • Universal basic income is something people talk about periodically, but to the best of my knowledge no-one has ever implemented it, apart from the odd very limited trial. It seems odd to add to the dictionary an acronym for something that does not exist in the real world, and may never do so.
  • I haven’t come across the other words and phrases, though they may be useful.   

For more new words

Newly emerging words that are being considered for entry are shared every Monday on the Cambridge Dictionary blog About Words About Words – Cambridge Dictionary blog – Commenting on developments in the English language

To see words of various years picked by various publishers, please see Words of the Year Archives – Language Miscellany

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