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.
put (someone or something) out to pasture or put out (someone or something) to pasture
to retire someone or something
We decided to put our old horse out to pasture and stop riding him.
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 different from the literal meaning of the words in it.