delirium

delirium — noun

1. a temporary medical condition in which a person has confused thoughts, cannot sp

1.nounB2
Definition

a temporary medical condition in which a person has confused thoughts, cannot speak clearly, and may see or hear things that are not real, usually caused by a high fever, a serious illness, or the effects of drugs or alcohol

Example

Zayd's fever was so high that he slipped into delirium, talking to people who were not in the room.

slipped into delirium — verb + preposition pattern for onset

The elderly patient was in delirium for two days after her surgery, unable to recognize her own daughter.

in delirium — prepositional phrase describing current state

Common collocations
  • in delirium
  • suffer from delirium
  • a state of delirium
  • delirium tremens
  • fever delirium
  • postoperative delirium
Synonyms
  • feverishness

    more general; refers to the physical symptom rather than the full mental state

  • hallucination

    focuses only on seeing/hearing unreal things, not the broader confusion state

  • disorientation

    a milder symptom; delirium includes disorientation plus other features

Antonyms
  • lucidity

    the state of being clear-minded and able to think normally

Grammar Patterns

delirium (caused by/from [cause])

in delirium

delirium + of + [cause]

Usage Note

In medical use, delirium is a specific clinical diagnosis (DSM-5), not simply confusion or disorientation. Distinguish from sense 1 (MEDICAL CONFUSION) versus sense 2 (WILD EXCITEMENT) by context: the medical sense is always associated with illness, drugs, or physiological causes.

Common Mistakes

He was in a delirium from winning the lottery.' (when describing a medical state)
He was delirious with joy after winning the lottery.
'delirium' in the medical sense should not be used for non-pathological excitement; use sense 2 or the adjective 'delirious' instead.

2. a feeling of wild excitement, extreme happiness, or intense emotional energy tha

2.nounC1
Definition

a feeling of wild excitement, extreme happiness, or intense emotional energy that takes hold of a person, especially during a celebration, a thrilling event, or a moment of great success

Example

The crowd was in a delirium of excitement when Madison scored the winning goal in the final minute.

in a delirium of [emotion] — prepositional pattern for figurative sense

Ryo experienced a brief delirium of joy when he heard that his music album had reached number one.

delirium of joy — common noun + of + emotion collocation

Common collocations
  • in a delirium of
  • delirium of joy
  • delirium of excitement
  • sheer delirium
  • pure delirium
  • erupt into delirium
Synonyms
  • ecstasy

    more spiritual or profound; can imply a trance-like state

  • frenzy

    more agitated and uncontrolled; can have a negative edge

  • euphoria

    longer-lasting; often drug-induced or medical in tone

  • elation

    milder and more restrained than 'delirium'

Antonyms
  • calm

    a state of quietness and emotional control

Grammar Patterns

delirium of [emotion/noun]

in a delirium of [emotion]

Usage Note

When used figuratively, delirium is always an extreme state — it would not describe mild enjoyment or ordinary happiness. Subject is typically a person or a crowd; the emotion is specified with 'of' (e.g., 'delirium of joy').

Common Mistakes

I felt a small delirium when I got a good grade.
I felt a delirium of joy when I won the competition.
'delirium' implies an intense, overwhelming feeling, not a mild positive emotion.

Word family

  • delirious
    adjectiveB2
  • deliriously
    adverbC1
  • delirium tremens
    nounC1

Synonym discussion

Sense: noun/1

Delirium, hallucination, dementia, and disorientation all describe mental states involving confusion, but they differ in cause, duration, and scope. Delirium is a temporary, acute condition — often brought on by fever, infection, or substance withdrawal — that includes confused thinking, disrupted attention, and sometimes hallucinations. Hallucination refers specifically to a sensory perception (seeing, hearing, or feeling something) that is not real; it can occur as part of delirium or on its own. Dementia is a chronic, progressive decline in cognitive function (common in Alzheimer's disease) that develops slowly over years, unlike delirium's sudden onset. Disorientation is a narrower symptom — being confused about time, place, or identity — that can appear in delirium, dementia, or even temporary stress. For example: 'The patient's delirium cleared once the infection was treated.' vs. 'The visual hallucination made him think spiders were crawling on the wall.' vs. 'Grandmother's dementia has gradually worsened over the last five years.' vs. 'After the accident, she suffered from disorientation and could not remember where she was.'

delirium ↗hallucination ↗dementiadisorientation

Common collocations

Nouns

Phrases

  • a state of delirium
  • a bout of delirium
  • signs of delirium

Prepositions

Etymology

LatinEnglish

The word 'delirium' comes from Latin 'delirare', which literally means 'to go off the furrow' — a farming metaphor. 'De-' means 'away from' and 'lira' means 'a furrow or ridge between rows of crops'. A farmer who ploughed out of the straight furrow was said to be 'delirare', suggesting a mind that has wandered off its proper path. The medical sense appeared in Latin and entered English in the late 16th century, initially describing mental disturbance caused by illness. The figurative sense (wild excitement) developed later, by the early 19th century.