Pronunciation: (sī"ki-del'ik),[key] —adj. 1. of or noting a mental state characterized by a profound sense of intensified sensory perception, sometimes accompanied by severe perceptual distortion and hallucinations and by extreme feelings of either euphoria or despair.
2. of, pertaining to, or noting any of various drugs producing this state, as LSD, mescaline, or psilocybin.
3. resembling, characteristic of, or reproducing images, sounds, or the like, experienced while in such a state: psychedelic painting.
—n. 1. a psychedelic drug.
2. a person who uses such a substance. Also,psychodelic.