Take the Fall means: Accept the blame and possibly the punishment for another's wrongdoing
Example of use: "It was brave of him to take the fall for Danny like that."
Interesting fact about Take the Fall
Although the word “fall” originated in Old English, the origin of the idiom “take the fall” or “take a fall” meaning one incurs the blame for a misdeed perpetrated by another originated in the 1920s. At first, it was used only in criminal underworld slang; by the middle of the 1900s, the idiom was extended to less criminal types of blame.
