See also 368. SIZE .
- 1. Psychiatry. a form of mental illness marked by delusions of greatness, wealth, or power.
- 2. an obsession with doing extravagant or grand things. — megalomaniac, n. —megalomaniacal, adj.
- Psychiatry. a slowly progressive personality disorder marked by delusions, especially of persecution and grandeur. —paranoid, paranoiac, adj.