Hypocrisy (n.) - What mask do you wear?
Espousing a belief or promoting a practice that one does not believe in or practice.
History & Etymology
Hypocrite is derived a compound Greek word hypokritēs(hoop-ok-ree-tace'). Formed from Hypo- meaning under, and -kritikē meaning judge or critic. This word was commonly used to refer to stage actors, meaning performer under a mask. It’s use in the New Testament in the Bible to refer two faced people and pretenders cemented the negative connotations it currently has.
In latin it became hypocrisies meaning roughly the same thing it means to us today, but it could also mean imitating someone's speech or gestures, like doing an impersonation.
As Vulgar Latin transformed into French it became Ypocrisie where it’s meaning solidified into the one we use today.