In economics, a capitalist is someone who owns capital, presumably within the economic system of capitalism.
Not all usages of the word assume actual ownership of capital. Some philosophers and political theorists, such as Ayn Rand and David Friedman, use "capitalist" to mean "an advocate of capitalism." Historically, some governments (such as the Soviet Union) used "capitalists" as a pejorative blanket term to refer to the governments of the Western Hemisphere and their supporters.