Idioms and How They Came About
An idiom is a phrase or expression with a special meaning: the meaning often cannot be understood from the meaning of the individual words in it. Idioms become part of a language, and they often make it sound more colorful. Let's look at the origin of some English idioms.
BACKSEAT DRIVER
This idiom comes from the habit many people have of giving unwanted advice from the backseat to the driver of a car. It means someone who tries to control things without having the authority to do so.