Governments don't actually have opposites, excluding anarchy, the lack of government. However, democracy is often considered the opposite of communism.
Communism
communism
totalitarianism
Totalitarian, although they always claim to be democracies.
Both are economic policies instigated by a government. They are on opposite sides of the spectrum in government involvement in economics. It is possible to say that communism is the eventuality of capatalism, but i wont get into that.
no you idiot it is a type of government
Democracy
communism
communism is this type if government!
A society with none of the hallmarks of capitalism, i.e. classes, wages, production for sale, government, armies. So Communism, a classless stateless society based on production for use.
Theocracy
A dictatorial version of capitalism.