What does delirious mean?
'Delirious' is an adjective with two related but distinct uses. In its literal, medical sense, it describes a person suffering from delirium: an acute, temporary disturbance of consciousness marked by confusion, disorientation, restlessness, hallucinations, and difficulty paying attention. This condition most often arises from severe fever, infection, drug or alcohol intoxication or withdrawal, or other serious illness, and it is considered a medical concern requiring attention. The word also carries a vivid figurative sense, describing someone overcome by wild excitement or intense happiness — fans may grow 'delirious with joy' at a concert, or a team's supporters may be 'delirious' after an unexpected victory. Derived from the Latin 'deliriare,' meaning literally 'to go off the furrow,' the word evokes the image of a plough slipping out of its intended line — a mind straying from its normal path. Its flexibility between clinical gravity and emotional exuberance makes it a richly expressive addition to both formal and everyday vocabulary.
Suffering from delirium; acutely confused and disoriented, often with hallucinations, typically due to fever, intoxication, or serious illness.
"The fever left him delirious for three days before it finally broke."
This is the primary, literal sense.
Wildly excited or overjoyed; in a frenzy of enthusiasm or delight.
"She was delirious with happiness when she learned she'd won the scholarship."
Informal and figurative; almost always paired with an emotion such as joy, excitement, or delight.
The Latin root of 'delirious' literally means 'to go off the furrow' — as if a plough has jumped its track, your mind has wandered off course.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of delirious
Delirious derives from the Latin verb 'deliriare,' meaning 'to go off the track or furrow,' formed from 'de-' (off, away) plus 'lira' (furrow), the same root that gives us 'lurid.' The term entered English in the early modern period via the noun 'delirium,' which physicians used for states of mental derangement associated with fever and disease. The figurative sense of ecstatic excitement developed later through natural extension, applying the image of a wandering, unmoored mind to overwhelming emotion rather than illness.
Related word forms
How delirious is actually used
The literal medical sense is neutral to negative, describing a genuine clinical condition. The extended sense — 'delirious with joy' — is informal and positive, common in journalistic and conversational English. Context usually makes clear which sense applies.
Easily confused with delirious
Delirious is the adjective describing someone in the state, while delirium is the noun naming the state itself.
Ludicrous means absurd or laughably ridiculous, while delirious refers to a frenzied mental state of confusion or extreme excitement.