(rare) Dream-like experiences or qualities; dreaminess.
1976, Neuropsychiatry and the War, p. 108:Following great explosions two forms of mental trouble have been found so frequently that other manifestations have become almost exceptional. These are mental confusion and delirious oneirism.
1990, Paul Ricœur, Time and Narrative, vol. 2, p. 138:With an almost imperceptible touch, the narrator connects up this oneirism of names with the premonitory signs of the vocation that Remebrance is said to recount.
(psychiatry) A state of abnormal consciousness in which dream-like experiences and hallucinations happen while awake.