hallucinative

noun

1. 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.
2. the sensation caused by a hallucinatory condition or the object or scene visualized.
3. a false notion, belief, or impression; illusion; delusion.

noun

1. the alleged perception of an object when no object is present, occurring under hypnosis, in some mental disorders, etc

n.

in the pathological/psychological sense of “seeing or hearing something which is not there,” 1640s, from Latin hallucinationem (nominative hallucinatio), from past participle stem of hallucinari (see hallucinate). Hallucination is distinct from illusion in not necessarily involving a false belief. Related: Hallucinations.

n.

1. False or distorted perception of objects or events with a compelling sense of their reality, usually resulting from a mental disorder or drug.
2. The objects or events so perceived.

A false perception that appears to be real, as when, for example, a man dying of thirst in a desert thinks that he sees a lake. (See also delusion.)