The term Rightist refers to someone on the 'right' side of the political spectrum. Politics on the 'right' usually imply taking positions in favor of the traditional system of a society, including its traditional values and its traditional ruling institutions. Compare: leftist.
It is widely accepted, however, that there is not just one dimension of political thought, so that people can unambiguously be classified as 'right' or 'left'. Nonetheless, the political spectrum theory still has wide currency.