Determine the real meaning of the capitalized words.Johnny really put HIS FOOT IN HIS MOUTH at the party last night.

Idioms are words or phrases that say one thing but mean something else.  In other words, their meaning is not what it first appears to be.  For example, to say “break a leg” does not really mean someone is to break a leg but, as in the entertainment world, it means to give a great performance.