The Gita sums up the definition of a hypocrite as follows:
A person who pretends not to care about the body,
but who really keeps on wishing for enjoyable things
is called a hypocrite.
Such a person is a fool.
The Bhagavad Gita, Chapter 3, verse 6
In order to attain Oneness with God, the Gita teaches that we must become detached from the feelings and desires created by our bodies. The above verse warns against faking piousness and pretending detachment rather than striving to achieve it.
Hypocrisy is tempting to those who wish to appear devout and even to those who wish to view themselves as devout. But in the Gita Lord Krishna repeatedly tells us that just trying to become close to God is very good and leads to happiness and wisdom. Regardless of how we view God or our truth, we should face ourselves honestly and be real.
Learn more about the the Gita in my book, The Gita, A New Translation of Hindu Sacred Scripture.