mustn’t

وَجَبَ (على ...)‏ \ have got to: to must: You’ve got to be more careful. must: (p.t.. had to neg.. mustn’t) to have to; ought to: We must take care of our children. You mustn’t hit that little boy. ought: (oughtn’t; no other forms) v. aux. (showing what is one’s duty, or what is right or usual or probable) should: You ought to help your father. She ought to be asleep by now. He doesn’t work as hard as he ought (or ought to, or ought to do). shall: (stressed) with any subject, to express the speaker’s firm intention: He shall go, whether he wants to or not., (Use must in reported speech: I said that he must go). Other forms can be used but may be confusing.