The term 'PREVENTS, LEGALLY' can be summarized by two crossword solutions: ESTOPS (6 letters) and ENJOINS (7 letters). ESTOPS is a legal term that means to prevent or stop someone from doing something. It is typically used in the context of a court order or injunction. ENJOINS is another legal term that means to command or order someone to do something. It is also typically used in the context of a court order or injunction. Both terms are commonly used in legal proceedings and are often used interchangeably.