Idiomatic expressions(idioms)

It is a group of words,whose combined meaning is not the same as the ordinary meaning of the individual words.It is used to express something that other words do not express as clearly or as cleverly.Like a figure of speech,an idiom expression gives english its color and vitality,it is frequently used in daily speech and appear in newspapers,books,television shows,and movies.it tend to be informal,allowing your reader or listener the opportunity to obtain a more colorful image of what you are saying.

example        

apple of one's eye               special favorite,beloved person or thing
an  arm and a leg                an exorbitant amount of money
couch potato                       a person who enjoys relaxing at home,especially watching television