What is Bail Bondsman?

Legal Definition
A bail bondsman, bail bondsperson, bail bond agent or bond dealer is any person, agency or corporation that will act as a surety and pledge money or property as bail for the appearance of persons accused in court. Although banks, insurance companies and other similar institutions are usually the sureties on other types of contracts (for example, to bond a contractor who is under a contractual obligation to pay for the completion of a construction project), such entities are reluctant to put their depositors' or policyholders' funds at the kind of risk involved in posting a bail bond. Bail bond agents, on the other hand, are usually in the business to cater to criminal defendants, often securing their customers' release in just a few hours.

Bail bond agents are almost exclusively found in the United States and its former commonwealth, the Philippines. In most other countries the practice of bounty hunting is illegal. The industry is represented by various trade associations, with the American Bail Coalition forming an umbrella group in the United States.
-- Wikipedia
Legal Definition
the person who puts up the bond that is necessary to get the release of the accused.