It implies an uncommon personality, so that an individual behaves in a manner that is out of conformity with accepted norms. True eccentrics are often beset with phobias, obsessions and anxieties, their conduct being quite inexplicable. Eccentricity is frequently regarded as one of the signs of geniuses.
Among the famous eccentrics are Friedrich von Schiller, who worked with his feet placed on ice for a time and inhaling the flavour of rotten apples, and Emile Zola, who counted the gas jets in every street through which he walked or drove.