There are several synonyms for the word "assentatious" which means inclined to show off or seek attention. One such word is "ostentatious" which refers to a showy display meant to impress others. "Pretentious" is another term used to describe someone who behaves in a way that suggests they are more important or talented than they really are. "Extravagant" is a synonym that suggests excessive or wasteful spending. "Flamboyant" implies a bold or striking style that stands out from the norm. Lastly, "flashy" is a synonym that refers to something that is eye-catching or attention-grabbing in a way that is often seen as superficial.