vexatious

adjective

1. causing vexation; troublesome; annoying: a vexatious situation.
2. Law. (of legal actions) instituted without sufficient grounds and serving only to cause annoyance to the defendant.
3. disorderly; confused; troubled.

adjective

1. vexing or tending to vex
2. vexed
3. law (of a legal action or proceeding) instituted without sufficient grounds, esp so as to cause annoyance or embarrassment to the defendantvexatious litigation