1703, "wandering in the mind, affected with delirium" (as a result of fever or illness), from stem of delirium + -ous. The earlier adjective was delirous (1650s). Figurative sense of "characterized by or proceeding from wild excitement or exaggerated emotion" is by 1791. Related: Deliriously; deliriousness.
a crowd of delirious baseball fans
delineation
delinquency
delinquent
deliquesce
deliquescent
delirious
delirium
deliver
deliverable
deliverance
delivery