An idiom is a group of words, or in other words, a phrase that has a meaning different from the literal meaning of the words in it.
in contempt of court
disrespecting a judge or courtroom procedures
The woman was in contempt of court when she refused to sit quietly during the trial.
List of common idioms, their meanings and examples of their usage in sentences
A group of words which have a different meaning when used together from the one they would have if you took the meaning of each word separately.