Eccentric..

 

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The popular usage, eccentricity refers to unusual or odd behavior on the part of an individual. This behavior would typically be perceived as unusual or unnecessary, without being demonstrably maladaptive. 

Eccentricity is contrasted with "normal" behavior, by which individuals in society solve given problems and pursue certain priorities in everyday life. People who consistently display benignly eccentric behavior are labelled as "eccentrics.

Some famous people may be eccentric whose personal behavior strikes others as odd. Albert Einstein picked up cigarette butts off the street to get tobacco for his pipe; Howard Hughes spent entire days on a chair in the middle of the supposedly germ-free zone of his Beverly Hills Hotel suite.

The composer Robert Schumann believed that his musical compositions were dictated to him by Beethoven and other deceased luminaries from their tombs; and Charles Dickens is said to have fended off imaginary urchins with his umbrella as he walked the streets of London.