What is the origin of the idiom "copycat" and when to use it?

The idiom "copycat" originated in the mid-20th century, combining the words "copy" and "cat." The term draws on the mimicry behavior observed in cats and is used to describe someone who imitates or emulates the actions, ideas, or style of another person. This expression is often used in a playful or colloquial manner to tease or criticize individuals who lack originality and instead replicate the behavior or work of someone else.