Tortious interference , also known as intentional interference with contractual relations , in the common law of torts , occurs when a person intentionally damages the plaintiff 's contractual or other business relationships. This tort is broadly divided into two categories, one specific to contractual relationships (irrespective of whether they involve business), and the other specific to business relationships or activities (irrespective of whether they involve a contract).

http://en.wikipedia.org/wiki/Tortious_interference