Hypocrisy is a performance offstage.

Duke Ling of Qi, in the Spring and Autumn period, loved to dress the women of his palace as men. He delighted in the sight of women walking in trousers with swords at their sides. But when word spread beyond the walls and even ordinary commoners began to follow the fashion, the duke was dismayed. He at once issued an order: "If any woman among the people dresses as a man, tear her clothes and cut her sash." Once the law was enforced, the women in the streets stopped cross-dressing. Yet the women within the palace went on dressing as men. The ban had no effect. One day the minister Yan Ying (Master Yan) met the duke. The duke asked, "I have already forbidden it — why does it not stop?" Yan Ying replied: "Your Majesty has them dress so within and forbids it without — this is like hanging an ox's head at the gate while selling horse meat inside." The duke, ashamed, forbade cross-dressing within the palace as well. Within a month the custom vanished throughout the whole state. In later ages this anecdote was reshaped into the form "hanging a sheep's head, selling dog meat" (懸羊頭賣狗肉), appearing in the Song-dynasty Chan Buddhist record Wudeng Huiyuan, and was condensed into the more memorable four characters 羊頭狗肉. Originally it was "an ox's head and horse meat," but later generations changed it to "a sheep's head and dog meat" — because the contrast is sharper.

The root of the English "hypocrisy" is the ancient Greek "hypokrisis" (ὑπόκρισις). It comes from the verb "hypokrinomai," and its structure is this: hypo (beneath, behind the mask) + krinein (to judge, to distinguish, to answer). Translated literally, "to answer from beneath." Beneath what? Beneath the mask. In classical Greek theater, the actor was called "hypokrites." Actors of the time spoke through large masks; to the audience the mask was the character's face, but to the actor himself it was "beneath the mask." Thus "one who judges and speaks from beneath the mask" — that was the hypokrites, the actor. The word originally carried no contemptuous meaning. Aristotle, in his "Rhetoric," used "hypokrisis" in the neutral sense of "the art of acting on stage, the use of the voice." The problem began after the 1st century BCE. When the Greek-speaking Jewish community translated the Hebrew scriptures into Greek (the Septuagint, LXX), they rendered "the false one, the masked one" as hypokrites. Decisive was Jesus calling the Pharisees "hypocrites" (hypokrites) in the New Testament. In Matthew 23 alone it appears seven times — "Woe to you, scribes and Pharisees, hypocrites!" Through this religious usage, the sense of "actor" disappeared and only "one whose outside and inside differ" remained. The English "hypocrisy" first appeared in English writing around 1200, by way of the Old French "ypocrisie." The medieval English poet Geoffrey Chaucer portrayed the Pardoner in his Canterbury Tales as a "hypocrite."