Mukh Gyani is a term attribute to that person which have knowledge, but do not follow life according to that. If a person knows about Sikhi, he knows everything about Guru Granth Sahib, he understands it's philosphy, he sing that philosphy in public. He tell all this to public but if he himself do not follow the philosphy such person is called MUKHGYANI. Punjab is Adda of MukhGyanis.
MUKHGYANI = Mukh + Gyani
i.e Knowledgeable but now follower