Rebore

A replica, deactivated gun or sometimes and air pistol which has been modified to allow it to shoot live ammunition. The term refers to the fact that the gun's barrel has been re-bored (drilled out), as often deactivated weapons have had their barrels blocked with metal.

The term also refers to a copy or fake and can be used to describe a person or object which resembles another.

The origins of this word can be found in hip hop, rap and British grime music scenes and also in use on the inner-city streets of many towns in the UK and US.

means that it is fake or just absolutely rubbish or shit

Rebor, origniated from the word "reborn" as replica guns would be reborn into guns which can actually shoot, , first refered to 'fake' weapons, fake guns usually, however it is now used universally.