ENGLISH
REFERENCE

delirium

n.
C1 Advanced US //dɪˈɫɪɹiəm// UK //dɪlˈɪɹiəm// delir·i·um

n. a state of being very confused and having strange thoughts, often because of a high fever or a serious illness. You might feel like you are seeing things that are not there.

n. a state of mental confusion characterized by incoherent speech and hallucinations, typically resulting from a high fever or severe illness. Often used to describe a temporary loss of mental clarity.


SIMPLE

The patient suffered from delirium after the surgery.

CONTEXTUAL

Doctors monitored the patient closely for signs of delirium, as high fevers can cause severe confusion in the elderly.

COMPLEX

The sudden onset of delirium often signals a systemic infection or metabolic imbalance, requiring immediate intervention to prevent further neurological damage.

Synonyms
Origin

Borrowed from Latin dēlīrium (“derangement, madness”).

© 2026 English Reference