Here are 10 of the most common idioms that are easy to use in daily conversation: “Hit the hay.” “Sorry, guys, I have to hit the hay now!” ... “Up in the air” ... “Stabbed in the back” ... “Takes two to tango” ... “Kill two birds with one stone.” ... “Piece of cake” ... “Costs an arm and a leg” ... “Break a leg” More items... Sep 29, 2017