a sensory experience of something that does not exist outside the mind, caused by various physical and mental disorders, or by reaction to certain toxic substances, and usually manifested as visual or auditory images.

the sensation caused by a hallucinatory condition or the object or scene visualized.

a false notion, belief, or impression; illusion; delusion.

noun

experience , fact , reality , truth

noun

aberration , apparition , fantasy , figment of the imagination * , head trip , illusion , mirage , phantasm , phantasmagoria , phantom , trip * , vision , wraithnotes:hallucination is from disturbed sensory perceptions; delusion is from disturbed thinking , delusion , ignis fatuus , phantasma , will-o\'-the-wisp , phantasmagory , chimera , delirium tremens , dream , fallacy , self-deception