Short and simple, hemophilia is a condition that prevents the blood from clotting. The term "free-bleeder" refers to hemophilia.
WebMD defines hemophilia as "a group of hereditary genetic disorders that impair the body's ability to control blood clotting or coagulation, which is used to stop bleeding when a blood vessel is broken." Hemophilia A (clotting factor 8 deficiency) is the most common form of the disorder, present in about 1 in 5,000 - 10,000 mail births.
Click here to view the WebMD page on hemophilia to understand the basics.