Depends on how far you want to go left. On the more extreme side, these people want to abolish capitalism entirely and replace it with a communal system (workers owning the means of production). Democratic socialism is a very moderate form where capitalism is kept, but people get a fair chance of living in the system (usually through monetary assistance), no matter what family they come from and what their abilities are.
Liberals are pro free market and capitalism. Leftists are pro social programs and taxing the rich.