Mustn't

The contraction of "must not," 'mustn't' is an auxiliary verb expressing prohibition, strong obligation not to do something, or the lack of necessity in specific situations. It emphasizes a rule, a strong recommendation against an action, or the certainty that an action should not or does not need to occur. 'Mustn't' signifies a stronger restriction than "shouldn't," implying a potential consequence if the rule is violated, thus enforcing an imperative. The core meaning is 'to be forbidden from doing something,' or 'a strong discouragement from doing something'. It is frequently used to give instructions, warnings, and prohibitions.

Mustn't meaning with examples

• You mustn't touch the wet paint; it's still drying, and you'll ruin your clothes! The sign clearly states it, and your parents will be upset, so it's a very firm rule. Consider this a direct command; it's important to obey for both cleanliness and safety. So please be careful.
• We mustn't disclose the secret recipe to anyone, especially competitors. Our business depends on it! This is a matter of utmost confidentiality; revealing it would severely damage our company. It's a crucial business strategy, and failure could lead to major losses.
• If you go into the woods, you mustn't stray from the marked paths. There may be dangerous animals lurking nearby, therefore, this is very important for your safety. Keep a close eye on your surroundings at all times. This will help you stay safe, and return home.
• You mustn't worry about things that are beyond your control. It won't solve anything. Stressing excessively only drains your energy. Focus your attention where you can make a positive impact, rather than obsessing over the what ifs of the world.
• Children mustn't stay up all night. Sleep is vital for their growth and well-being. Adequate rest helps with their learning and helps to keep them alert. Therefore a regular sleep schedule is a must. It benefits everyone around them, too.