The crossword solution for the term 'obstruct legally' is 'ESTOP'. ESTOP is a legal term that means to prevent or prohibit someone from doing something. It is a form of legal injunction that is used to prevent a person from taking a certain action. ESTOP is often used in cases where a person has a legal right to do something, but another party wishes to prevent them from doing so. ESTOP is also used to prevent a person from making a claim or asserting a right that they may have.