What is the full form of VIP ?

VIP - Very Important Person

A "VIP" is a person of great importance and status, and require special privilege and security specially in a public area. 

The most common examples of VIP persons include: leaders and politicians, movie stars, senior level officers of defense, rich employers, senior level government officers etc. 

Sometimes instead of a person, a "service" could be called VIP which is an alternative term used for "premium". Suppose in a movie hall the premium tickets are reserved for VIP guests that can be purchased by anyone who require a high level of comfort and separation from common people.