yellow peril

noun Disparaging and Offensive.

1. (in historical contexts) the alleged danger that predominantly white Western civilizations and populations could be overwhelmed by Asian peoples.
2. the Asian peoples regarded as presenting such a danger.

noun

1. the power or alleged power of Asiatic peoples, esp the Chinese, to threaten or destroy the supremacy of White or Western civilization

A supposed threat to the United States posed by Japan and China. The phrase arose in the late nineteenth century, at a time when Japanese and Chinese immigration to America was meeting resistance and when Japan was growing as a military power. (See internment of Japanese Americans.)