to delirate v.n. [deliro, Latin.] To dote; to rave; to talk or act idly. Dict.
Samuel Johnson’s Dictionary – selections from the 1755 work that defined the English language, edited by Jack Lynch
DELIRIUM. – A condition of mental excitement with confusion and sometimes delusions. It is not a disease but a symptom set up by disorder in the brain, or toxins in the blood. Some drugs cause it, such as opium. The delirious patient should not be left alone.
The Illustrated New Universal Reference Book, Oldhams Press Ltd, 1933
Delirium, n. Disordered state of mind with incoherent speech, hallucinations and frenzied excitement; great excitement, ecstasy;
The Concise Oxford English Dictionary, 5th Edition, Oxford University Press, 1964
Delirium XVI. – L. delirium, f. delirare deviate from a straight line, be deranged, f. DE- 2 + lira ridge between furrows. Hence delirious XVIII.
The Oxford Library of Words and Phrases III. Word Origins, Guild Publishing, London, 1988