A more thorough explanation:

Definition: A vexatious lawsuit is a legal action that is brought without any good reason or with malicious intent. It is also known as a vexatious suit or vexatious litigation. This type of lawsuit is intended to harass, annoy, or cause unnecessary expense to the defendant.

Examples:

• A person files a lawsuit against their neighbor for playing music too loudly, even though the neighbor has not violated any noise ordinances.
• An individual sues their former employer for wrongful termination, even though there is no evidence to support their claim.

These examples illustrate how a vexatious lawsuit can be brought without any legitimate reason or evidence. The purpose of such a lawsuit is to cause inconvenience and expense to the defendant, rather than to seek justice or compensation for a legitimate grievance.