vandalism

action involving deliberate destruction of or damage to public or private property. Unless it's a really cool graffiti.

"... look at that tag that someone painted in a wall that does not own and it's very ugly, such vandalism.."

".. look at that cool graffity, doesn't matter if he had permission or not that is definitelly not vandalism.."

"... I am going to google the vandalism definition that fits my needs..."