delusion
US /dɪˈluː.ʒən/
UK /dɪˈluː.ʒən/

1.
delirio, illusione
a belief that is not true and is not based on reality, especially as a symptom of mental illness
:
•
He suffers from the delusion that he is a famous rock star.
Soffre del delirio di essere una famosa rock star.
•
It was a common delusion among the patients.
Era un delirio comune tra i pazienti.
2.
illusione, inganno
the state of being deceived or misled
:
•
He was under the delusion that he could fly.
Era sotto l'illusione di poter volare.
•
Living in a constant state of delusion can be dangerous.
Vivere in uno stato costante di illusione può essere pericoloso.