gran·di·ose (gr?n?d?-?s?, gr?n?d?-?s?)adj.1. Characterized by greatness of scope or intent; grand: a grandiose plan to develop the city’s waterfront.2. Characterized by excessive self-importance or affected grandeur; pompous: “It’s important … for judges not to be rattled by political attacks into grandiose assertions of judicial supremacy” (Jeffrey Rosen).[French, from Italian grandioso, from grande, great, from Latin grandis.]gran?di·ose?ly adv.gran?di·os?i·ty (-?s??-t?) n.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.