Definition & Meaning of "scream blue murder"in English

What is the origin of the idiom "scream blue murder" and when to use it?

The exact origin of the idiom "scream blue murder" is uncertain, but it is believed to have emerged in the late 19th or early 20th century. This phrase can be applied to various situations, such as encounters with spiders, unexpected events, or situations that evoke strong negative emotions. It is often used to convey a sense of surprise, shock, or frustration, emphasizing the person's heightened emotional state.