The term LEGALLY PREVENTS can be summarized as 'estops, ' which is a legal term that means to prevent or prohibit someone from doing something. Estoppel is a legal doctrine that prevents a person from denying or asserting something contrary to what was previously established by their own actions or words. It is used to prevent a person from making a claim or taking a position that is inconsistent with their prior statements or actions. Estoppel is often used in contract law to prevent one party from going back on their word or changing the terms of an agreement.