An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.
Idiom:
put the words into (someone's) mouth
Meaning:
to say or suggest something for someone else, to speak for someone else without his or her permission
Example:
My friend always wants to put the words into my mouth before I have a chance to speak.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is a group of words, or in other words, a phrase that has a meaning other than its literal meaning of the words in it.