2) Usually involves a certain amount of skill.
3) Usually provokes thought in audience.
4) Commonly refers to visual arts, such as paintings, sculptures, etc.
5) Most importantly, interpretation and judgment of art tends to be controversial.
Taro Okamoto, an artist, was quoted as saying: "Art is a bang!" This is also a quote from Deidara of the manga/anime Naruto, a fictional character © Masashi Kishimoto.
Also: That produced by an "artist". It comes in many forms:painting, pencil-drawing, sculpture, etc. The medium isn't important as long as the creation is unfathomable to all but the exceedingly rich and outstandingly gay, who only pretend to understand it anyway and write protracted essays on it aimed at the terminally dull. Amongst those 2 classes of people a piece of art will often engender much chin-rubbing in bizarrely-lit art galleries. The practitioners of art are invariably pretentious individuals who consider themselves superior to all other people. In fact some artists take up the occupation in order to further remove themselves from normal, right-thinking people.