What is a capitalist society?

There's no such thing. Capitalism is a type of economic system characterized by private ownership of capital and the use of such to generate a private profit; it is not a social or political system. Capitalism has no moral precepts or ethical code, and therfore cannot be the basis of a society. The results of capitalism on society, however, lead to a culture that prioritizes and focuses on seeking short-term self-interest and financial profit. The system is designed so people who live in capitalism are too busy focusing on trivial things such as making ends meet and dealing with business on a daily basis, resulting in an unintellectual population that is largely apathetic to non-financial and non-short term interests. Interestingly enough, if Capitalism was used as the basis of a society, it would be self-destructive; because Capitalist ideals would make it justifiable to destroy Capitalism so long as you can make a personal profit doing so. In capitalism, people are forced to pursue their financial self interest even if it harms others or the community because they require the money to acquire the basic necessities for life. The adage "the rich man will sell you the rope you use to hang him" would characterize such a society.