Being ostentatious means to show off or display wealth or knowledge in a flashy or exaggerated way. There are several synonyms for the term including pretentious, showy, flamboyant, grandiose, and extravagant. When someone is being pretentious, they are acting as if they are more important or knowledgeable than they actually are. Showy implies that someone is putting on a display in order to attract attention. Flamboyant suggests a display of exaggerated or dramatic behaviour. Grandiose implies an effort to impress others with excessive or grand gestures. Lastly, extravagant implies that someone is spending or showing off in an excessive or unnecessary manner.