13 letters · 18 points in Scrabble
noun illusory perception; a common symptom of severe mental disorder
noun a mistaken or unfounded opinion or idea
noun an object perceived during a hallucinatory episode
originDerives from the verb hallucinate, from Latin hallucinatus. Compare French hallucination. The first known usage in the English language is from Sir Thomas Browne.
Etymology from Wiktionary, CC BY-SA 3.0