Pijan muškarac ne smije pucati.

Croatian masculine adjectives can have a short form and a long form in the nominative singular.

• pijan = short form
• pijani = long form

In modern Croatian, both can appear before a noun, and both can mean drunk here. The version in your sentence, pijan muškarac, is perfectly possible. Pijani muškarac is also very common and may sound a bit fuller or more definite, depending on style and context.

So the sentence is not wrong at all; it is just using the shorter adjective form.

Muškarac is in the nominative singular because it is the subject of the sentence.

In Pijan muškarac ne smije pucati, the person doing the action is the drunk man, so Croatian uses the nominative.

You can also see agreement:

• pijan = masculine singular nominative
• muškarac = masculine singular nominative

If it were an object, the form would change, for example:

• Vidim pijanog muškarca. = I see a drunk man.

Croatian does not have articles like English a/an and the.

So muškarac can mean:

• a man
• the man

The exact meaning depends on context.

That means Pijan muškarac ne smije pucati could be understood as:

• a general statement: A drunk man must not shoot
• a specific statement: The drunk man must not shoot

Without extra context, both are possible.

The verb smjeti means to be allowed to, may.

So:

• smije = is allowed to / may
• ne smije = is not allowed to / may not / must not

In English, the best translation is often must not, because it expresses prohibition clearly.

So this sentence is about permission/prohibition, not ability.

Because smjeti and moći mean different things:

• smjeti = to be allowed to
• moći = to be able to / can

So:

• Ne smije pucati. = He must not shoot / He is not allowed to shoot.
• Ne može pucati. = He cannot shoot / He is unable to shoot.

Your sentence says the drunk man is forbidden to shoot, not that he is physically unable to.

Smije is the 3rd person singular present tense form of smjeti.

It is 3rd person singular because the subject is one man:

• (on) smije = he may / he is allowed to

A few present-tense forms of smjeti are:

• smijem = I may
• smiješ = you may
• smije = he/she/it may
• smijemo = we may
• smijete = you may
• smiju = they may

So muškarac ne smije is the correct agreement.

After modal verbs such as smjeti, Croatian normally uses the infinitive of the main verb.

So:

• smije pucati = may shoot
• ne smije pucati = must not shoot

This is similar to English may shoot, except Croatian does not need a separate word like to here.

Other examples:

• mora ići = must go
• može doći = can come
• želi spavati = wants to sleep

No. Pucati has several meanings depending on context.

It can mean:

• to shoot / fire
• to burst
• to crack / split

In this sentence, the natural meaning is to shoot, probably with a gun or firearm, because that fits the idea of prohibition: A drunk man must not shoot.

So the context tells you which meaning is intended.

Yes. Croatian word order is more flexible than English word order.

The given sentence:

• Pijan muškarac ne smije pucati.

is a normal, clear order.

Because pijan stands directly before muškarac, it describes the noun as part of one phrase: a drunk man.

A different order can slightly change the emphasis. For example:

• Muškarac ne smije pucati pijan.

This more strongly suggests:

• A man must not shoot while drunk.

That is very close in meaning, but the focus shifts a little from a drunk man to the condition of being drunk at the time of shooting.

Both the adjective and the verb have to agree.

For a woman:

• Pijana žena ne smije pucati.

For several men:

• Pijani muškarci ne smiju pucati.

Notice the changes:

• pijan → pijana / pijani
• smije → smiju in the plural

So Croatian agreement is important:

• adjective agrees with the noun
• verb agrees with the subject

In Croatian, the negative particle ne is usually written separately from the verb.

So:

• ne smije
• ne može
• ne puca

That is the normal pattern.

A few very common forms are written together, such as:

• nisam
• nemam

But smjeti does not behave like that, so ne smije is correct.