The term Russian can refer either the Russian language (q.v.) or any Russian person.
Russians are citizens of Russia; another sense of the term is less inclusive and is restricted to ethnic Russians living anywhere. Insofar as there is a Russian national character--that is, the following is of course by no means a scientific description with no exceptions--Russians are characterized by warmth, sincerity, high intelligence, pride, and poor self-esteem. Authors such as Tolstoy and Dostoyevsky have made the Russian national character highly recognizable.
See also: Russian roulette