Idioms
An idiom is a type of phrase or expression that has a meaning that can't be deciphered by defining the individual words.
Idiom:
rail at (someone) about (something)
Meaning:
to complain loudly to someone about something
Example:
The customer was railing at the clerk about the bad service.
List of common idioms, their meanings and examples of their usage in sentences
Idioms are phrases which cannot be understood simply by looking at the meaning of the individual words in the phrase.