"What is a disclaimer?"
A disclaimer is a formal legal process by which a beneficiary (heir) states that they do not wish to accept a bequest under a will. It is also called a renunciation. For example, if you are named as a beneficiary under your uncle's will and your uncle dies and you are in the midst of a major lawsuit you might prefer not to accept the inheritance and instead let it pass to another family member. To do this you must meet the legal requirements of a disclaimer in your state. This may consist of filing a formal notice with the executor (person in charge of your uncle's will) and the court. To qualify as a disclaimer for federal estate tax purposes (so that your disclaimer won't be treated as a gift made by you) it must be done within nine months of your uncle's death. Importantly, you cannot accept any benefit from the property you are disclaiming. For example, you cannot cash a dividend check on the stock your uncle left you and then disclaim. Disclaimers are a powerful estate tax planning tool as well.