Idioms Part III

What are idioms?

Idioms are words, phrases or expressions which are commonly used in everyday conversation
by native speakers of English. They are often metaphorical and make the language more colourful. People use them to express something more vividly and often more briefly. 
They serve as an image or mental picture.  

Example:- Let the cat out of the bag :   If you let the cat out of the bag, you reveal a secret. 

N.B. It is important to remember that idiomatic expressions are used when speaking informally.
They are not used in formal exchanges.