Cliché

What is a cliché?

A cliche is a clever turn of phrase that has become so familiar that it does not seem so clever any more.
Examples of clichés are :

• Slippery as an eel 
• Pretty as a picture
• Happy as a lark
• Sharp as a tack
• Blind as a bat

Most grammar authors advise you to avoid them, especially in academic writing;  but in business writing, they do not seem to mind as long as the meaning conveyed is clear.