must

/mʌst/, /məst/ modal verb (must) (BE NECESSARY)

Definition

› used to show that it is necessary or important that something happen in the present or future: Seeing what others have and she lacks, she believes that she must have more. We must not surprise them (= it is wrong, dangerous, or forbidden). › If you say that you must do something, you can mean that you have a firm intention to do something in the future: I must call my sister later. › Must is sometimes used for emphasis: I must admit I enjoy these movies.

(Definition of must modal verb (BE NECESSARY) from the Cambridge Academic Content Dictionary © Cambridge University Press)