Negative imperative

You can already tell someone to do something: Dođi! Čekajte! Piši mi! Now for the opposite — telling someone not to. Serbian has a special little word for this, and in everyday speech it does almost all the work: nemoj.

nemoj and nemojte

nemoj is itself a command, so it changes with who you are talking to, exactly like an ordinary imperative: one form for one person you call ti, another for several people or for the polite vi.

There is a third form, nemojmo, for "let's not": Nemojmo da žurimo. — Let's not rush. You will hear it, but you can leave it aside for now.

What comes after nemoj

nemoj never stands alone — you have to say what not to do. There are two ways to add the verb, and both are fully correct.

1. nemoj + the infinitive — the dictionary form of the verb, unchanged: Nemoj zaboraviti pasoš. — Don't forget the passport. Nemoj vikati. — Don't shout. Nemojte otvarati vrata. — Don't open the doors.
2. nemoj + da + the present tense — and that present verb agrees with the person you are telling: Nemoj da zaboraviš pasoš.

This is the same choice you met with modal verbs (moram raditi / moram da radim). The difference is which one people actually reach for: after nemoj, the da version is the everyday spoken Serbian. Use it as your default.

Watch the agreement in the da version. After nemoj the present verb is second person singular; after nemojte it is second person plural. The two halves of the command always match.

A common slip: Nemojte da trčiš. The plural nemojte with a singular verb does not work. Fix the verb to match: Nemojte da trčite. And the infinitive never changes — Nemojte trčati, never Nemojte trčite without da.

The other way: ne + the imperative

You can also negate the ordinary imperative directly, with ne in front of it — the same ne you put before any verb. This is shorter and sounds firmer: it is what you find on instructions and signs, in set phrases, and with short everyday verbs.

So you have three ways to say the same thing, and they mean the same thing. Nemoj da diraš! is the one you will say most; Ne diraj! is a sharp, quick "don't"; Nemoj dirati! sits between them and reads as slightly more careful or written.

Which aspect?

Negative commands care about aspect. After ne the verb is the imperfective one: Ne otvaraj prozor. — Don't open the window. The perfective (Ne otvori!) is simply not said.

After nemoj both aspects are possible, and they say different things: the imperfective forbids the activity (Nemoj da otvaraš prozor. — don't be opening the window), while the perfective warns about one thing going wrong (Nemoj da padneš! — Don't fall! Nemoj zaboraviti! — Mind you don't forget!).

Signs and public notices

A sign addresses nobody in particular, so it uses neither form. It puts ne in front of a third-person singular verb with se: Ne puši se. — No smoking (literally: one does not smoke). Ne ulazi se. — No entry. You only need to recognise this one; nobody talks that way to a person.