Anti contest clause

An anti-contest clause is a provision in a will or trust meant to prevent the beneficiaries of said will or trust from objecting to its term(s). It does this by penalizing beneficiaries who challenge the will or trust, leaving them with nothing if their challenge fails. Anti-contest clauses are not always enforceable. Courts in Indiana and Florida do not allow anti-contest clauses; a beneficiary can bring a challenge in these states with no consequences if they lose. Other states require probable cause; anti-contest clauses will be enforced unless the challenging beneficiary had a sufficient reason to do so. If, however, a challenging beneficiary did have good reason to believe the will or trust was fraudulent–and they win the lawsuit–the anti-contest clause would not be enforced. 

Anti-contest clauses are more commonly called no-contest clauses. They are also sometimes called forfeiture clauses, noncontest clauses, terrorem clauses, and in terrorem clauses.