Simply, hard money loans allow you to borrow money using a real estate private lender instead of a bank. The definition of a hard money loan is that the real estate property serves as the “hard” asset to back the loan.
That's where the name comes from, by the way. There is a "hard" asset to back to loan, not from the loan being hard to get, or that the lender is tough!
Many real estate entrepreneurial investors who need to borrow money for their projects and are unable to get funded from their bank turn to a hard money lenders in Washinton DC to get their projects done. It is common for builders, developers, and fix and flippers to hard money for the differences—and the advantages—it brings.