An idiom is a phrase, saying, or a group of words with a metaphorical (not literal) meaning, which has become accepted in common usage.
An idiom’s symbolic sense is quite different from the literal meaning or definition of the words of which it is made. There are a large number of Idioms, and they are used very commonly in all languages. There are estimated to be at least 25,000 idiomatic expressions in the English language.
Idioms evolve the language; they are the building blocks of a language and civilization. They also have great intensity to make a language exciting and dynamic. Idiomatic expressions bring a spectacular illustration to everyday speech and provide compelling insights into the use of words, languages, and their speakers’ thought processes. Idioms have a sense of mystery and fun about them.
So what makes idioms difficult?
The answer is their meanings. Idioms are not easy to understand – especially for non-native speakers, because their intentions are usually symbolic. This characteristic makes them strange and difficult to understand for English learners.