Christ used a word from the Greek theater to describe people who are fakes.

HUPOKRISIS is the Greek word. It means play-acting. In the Roman and Greek theaters a character might appear on stage wearing a mask which was affixed to a short stick like an old fashioned fan. The mask might represent a villain and the actor was costumed accordingly. The actor might go off stage, quickly change his robe, and come back wearing a different mask depicting a hero. The Greek word for such a person is translated hypocrite, meaning a play-actor, a pretended. It referred to one who pretended to be what he was not. In the theater it was never used in a negative sense. However, Jesus never used it in a complimentary manner. It appears only in the gospels. The fact it appears 15 times means it was of vital concern to Christ. He does not like fakes.

Christ presses His illustration further. He describes these play actors as being like whitewashed tombs. They are beautiful and white on the outside, but inside they are full of dead men’s bones.  Inside they are lifeless.

There is even a deeper meaning understood by His listeners. In the month of Adar just before Passover graves and grave sights were whitewashed to identify them in order that people might avoid them. In that era for a person to touch a grave it was thought to contaminate them and make them unclean for Passover. By calling them whitewashed tombs Jesus was saying such hypocrites should be avoided.