[dɪˈl(j)uːʒn], (Noun)

Definitions:
- a false belief or judgement about external reality, held despite incontrovertible evidence to the contrary, as a symptom of serious mental illness
(e.g: he began to experience hallucinations, delusions, anxiety, and agitation along with dizziness and nausea)


Phrases:
- delusions of grandeur

Origin:
late Middle English (in the sense ‘act of deluding or of being deluded’): from late Latin delusio(n-), from the verb deludere (see delude)