A mask is a cover worn on the face to conceal one's true identity.  It is something, often a personal trait that disguises or conceals true emotion.

A persona is the role that one assumes or displays in public or society; one's public image or personality, as distinguished from the private inner self.

A façade is an artificial or deceptive front.  It is an barrier of artifice that makes something look better, larger or more imposing or elaborate than it really is.

A disguise is the act or an instance of disguising.  It is clothes or accessories worn to conceal one's true identity.  It is creating an appearance that misrepresents the true character of something or someone.  It is a pretense, misrepresentation or a false front.

A veneer is a thin surface layer.  It is a deceptive, superficial show or a façade.   It is an artificial surface that makes something look slicker or more polished than it is.

Camouflage is the method, act or result of concealing a person by making him or her appear to be part of the natural surroundings.  It is concealment by disguise or protective or deceptive coloring or clothing.