hallucinate

From Latin hallūcinātus, alternative form of alūcinātus, from alūcināri (to dream).

• IPA^(key): /həˈl(j)uːsɪneɪt/

• Audio (Southern England):

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hallucinate (third-person singular simple present hallucinates, present participle hallucinating, simple past and past participle hallucinated)

1. (ambitransitive) To seem to perceive things (with one or more of one's senses) which are not really present; to have visions; to experience a hallucination.

   Synonyms: imagine, see things

2. (artificial intelligence, of a model) To produce information that is not supported by the model's training data.
   • 2015 May 21, Andrej Karpathy, “The Unreasonable Effectiveness of Recurrent Neural Networks”, in Andrej Karpathy blog:

     In case you were wondering, the yahoo url above doesn’t actually exist, the model just hallucinated it.

   • 2021 September 14, Nouha Dziri, Andrea Madotto, Osmar Zaiane, Avishek Joey Bose, “Neural Path Hunter: Reducing Hallucination in Dialogue Systems via Path Grounding”, in arXiv:2104.08455 [cs]‎^[1], →DOI:

     Despite maintaining plausible general linguistic capabilities, dialogue models are still unable to fully discern facts and may instead hallucinate factually invalid information.

   • 2025 February 10, Debra Cassens Weiss, “No. 42 law firm by head count sanctioned over fake case citations generated by AI”, in ABA Journal‎^[2]:

     Rankin sanctioned Ayala $3,000 and kicked him off the lawsuit after the lawyer admitted incorporating the hallucinated AI-generated cases in the brief. Morgan and Goody were sanctioned $1,000 each.

• “hallucinate”, in OneLook Dictionary Search.