delulu

adjective

de·​lu·​lu di-ˈlü-lü 

slang

: having false ideas or beliefs : delusional

… the back story of the play, which initially featured Uta Hagen as Martha, the delulu grown daughter of a New England college president, and Arthur Hill as George, her husband, an associate history professor whose career has stalled.

—Alexandra Jacobs

especially : unreasonably self-confident especially in one's ability to achieve life goals

And although she added that it might be "pretty delulu to write a check like that to yourself and put it in your wallet," [actress Natasha] Rothwell is a firm believer in the law of attraction.

—Dan Heching

Word History

Etymology

shortening of delusional, with doubled final syllable, perhaps after lulu

First Known Use

2015, in the meaning defined above