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.
Idiom:
spoon-feed (someone)
Meaning:
to make something very easy for someone
Example:
He is a very strict teacher and never likes to spoon-feed his students.
List of common idioms, their meanings and examples of their usage in sentences
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.