Working Class: the vast majority of humanity. Everyone whose basic necessities for survival and physical as well as mental health is controlled by others. Despite the name, this class DOES include those who are unable to work.
Lesser Owning Class: Anyone who controls said necessities but at least employs or otherwise benefits people of the working class. These aren’t necessarily bastards but there should be as few of them as possible.
Parasite Class: The ones whose main or sole source of income is gaining wealth by having wealth already. Examples include landlords, billionaires borrowing against their stock portfolio and others whose enrichment removes money from the general economy while adding only to their own dragon hoard and/or mostly closed systems like stock markets. That these exist at all is one of the greatest atrocities allowed by mankind.