Idioms are phrases which cannot be understood simply by looking at the meaning of the individual words in the phrase.
keep up with the Joneses
to try to be the same as your neighbors (usually in matters related to money)
The man always worries about keeping up with the Joneses and he is always frustrated.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is defined as - a group of words in a fixed order that has a particular meaning that is different from the meanings of each word on its own.