な (Prohibitive)Do not, Don't (Prohibitive)

The ないでください form is used to make polite negative requests, similar to the English 'Please don't do [this]'. In comparison, the dictionary/non-past form of a verb + な expresses an extremely blunt or brusque command not to do something. The two forms have similar meanings (telling someone not to do something) but vary greatly in politeness level.

The てください form is used to make polite requests, similar to the English 'Please do [this]'. In contrast, the dictionary/non-past form of a verb + な expresses an extremely blunt or brusque command not to do something. The two forms have opposite meanings and are completely different in politeness levels (i.e. 'please do' vs. 'don't do!').

The dictionary/non-past form of a verb + な expresses a blunt command not to do something. In contrast, てごらん is a gentle encouragement to try doing something. For example, 食べるな！ means 'Don't eat it!' while 食べてごらん means 'Try eating it' Both are used toward someone of lower status, such as an adult speaking to a child.

The dictionary/non-past form of a verb + な expresses a blunt command not to do something. In contrast, たまえ expresses a strong, authoritative command to do something. For example, 食べるな！ means 'Don't eat it!' while 食べたまえ means 'I command you: eat it!' な is more casual than the formal たまえ, but both are used toward someone of lower status whom you have power over.

The dictionary/non-past form of a verb + な expresses a blunt command not to do something. In contrast, a verb stem + なさい expresses a strong but respectful command. For example, 食べるな means 'Don't eat it!' while 食べなさい means 'Eat it!' Despite being derived from an honorific verb, なさい is still a command and is used with lower-status people or children, not superiors.

The dictionary/non-past form of a verb + な expresses a blunt command not to do something. Similarly, ないで attached to the negative stem of a verb is a more casual and gentle request. For example, するな is a strong way of saying 'Don't do it!' while しないで is a softer, more casual way of saying '[Please] don't do it.'