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:
explain (something) away or explain away (something)
Meaning:
to explain something so that it seems less important
Example:
The sales clerk tried to explain away the problem with the sales receipt.
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.