When you hear voices in your head and believe they are the voice of the President or the voice of Jesus communicating personally with you, this is an example of a delusion.
Labored under the delusion that success was at hand.
Delusions of persecution.
Origin of delusion
- Middle English delusioun from Latin dēlūsiō dēlūsiōn- from dēlūsus past participle of dēlūdere to delude delude
From American Heritage Dictionary of the English Language, 5th Edition