What is a no-contest clause?
Essentially, a no-contest clause forces an heir who brings and loses a will contest to forfeit his inheritance under the challenged will. Consequently, only heirs who stand to inherit more money if there were no will are likely to contest the will. Therefore, effective use of a no-contest clause generally requires mathematics, psychology and measured generosity. In other words, a no-contest clause will be most effective if you give the heir you are seeking to disinherit a large enough share of your estate that contesting the will is not worth the risk.