If you describe someone's behaviour as ostentation, you are criticizing them for doing or buying things in order to impress people.
例句
Consumers are abandoning the excess and ostentation of the 1980s...消費者摒棄了20世紀80年代鋪張擺闊的陋習。On the whole she had lived modestly, with a notable lack of ostentation.大體上說，她生活儉樸，不事張揚。
英漢詞典釋義
n.
擺闊,講排場
I don’t like the ostentation of their expensive life-style.他們生活奢侈,愛擺闊,我不敢恭維。
英英詞典釋義
Noun
1. a showy outward display
2. lack of elegance as a consequence of being pompous and puffed up with vanity