背影的英文是 "silhouette"。这个词来源于法语词语 "silhouette"，意思是"黑影"或"剪影"。

例句：

The silhouette of the building was beautiful against the setting sun. (建筑的背影在落日下格外美丽。)

The silhouette of the man was distinct against the white wall. (那个男人的背影在白墙上显得格外醒目。)