A more thorough explanation:

An anti-contest clause is a legal term that refers to a provision in a will or trust that aims to prevent beneficiaries from challenging the terms of the will or trust. This clause is also known as a no-contest clause, forfeiture clause, noncontest clause, terrorem clause, or in terrorem clause.

For example, let's say that a wealthy person creates a trust that leaves their assets to their children. The trust includes an anti-contest clause that states that if any of the children challenge the terms of the trust, they will lose their inheritance. If one of the children decides to challenge the trust, and the court finds that the challenge is without merit, that child will lose their inheritance.

However, anti-contest clauses are not always enforceable. In some states, such as Indiana and Florida, anti-contest clauses are not allowed. In other states, anti-contest clauses will be enforced unless the challenging beneficiary had a sufficient reason to do so. If a beneficiary had good reason to believe the will or trust was fraudulent and they win the lawsuit, the anti-contest clause would not be enforced.

In summary, an anti-contest clause is a provision in a will or trust that discourages beneficiaries from challenging the terms of the will or trust by penalizing them if they do so.