Definition - What does Vexatious Litigation mean?
Vexatious litigation is litigation that is taken specifically for the purpose of harassing the defendant and that has no legal basis for being taken. Vexatious litigation is thrown out at the earliest court opportunity and the claimant can be sued by the defendant for the same as well as being held legally responsible for wasting court time.
Justipedia explains Vexatious Litigation
There are many reasons why a person would have vexatious litigation brought against them, but the basis for all reasons would be considered without merit by the court. It is done for publicity in many cases or to try to wreck a person's or company's good name.