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.
come into (some money)
to get possession of some money, to inherit some money
The man came into much money which he later donated to charity.
List of common idioms, their meanings and examples of their usage in sentences
Idioms can be a powerful linguistic tool only when they are used in the right way in the right places.