Barratry in
criminal law is when a lawyer or
plantiff frequently carries out legal action, often of neglible merit, with the intent to annoy or harrass.
Such cases could be thrown out for being frivolous if it can be proven that the lawyer and his plantiff proceeded with legal actions knowing that the case had no merit, did not seek to reinterpret existing legal statutes or decisions, and/or the plantiff is relying on evidence or facts so dodgy that their lawyer should have obviously identified. In the United States Federal Rule 11 states that the onus is on the lawyer to exercise due diligence and investigate the integrity of the plantiff's arguments before filing a suit.
A vexatious suit involves filing a frivolous suit with malice - designed to injure a respondant through the inconvenience and damage to reputation that ensues from a law suit.
In many jurisdictions sanctions exist against lawyers and plantiffs for instituting frivolous or vexatious lawsuits.
The term barratry also refers to the practice banned by the Catholic church of selling or buying spiritual favours that are normally rendered by members of clery. The 'temporal' items identified by Gregory the Great as part of an illicit sale include munus a manu (material advantage), munus a lingua (commendations) and munus ab obsequio (homage). These things include ceremonies like grace, the sacraments and sacramentals, and religious items like holy water and crucifixes, as part of a private sale. Barratry in this sense is better known as simony.
And barratry can also be used to describe mutiny on a ship instigated by the captain or master.
http://www.lectlaw.com/def2/u087.htm,
http://www.newadvent.org/cathen/14001a.htm