Navodno je muzej otvoren.

Navodno means apparently, reportedly, or allegedly, depending on context.

In this sentence, it tells you the speaker is not presenting the information as a confirmed fact. They are saying that this is what they have heard or what is being said:

• Navodno je muzej otvoren. = Apparently / reportedly, the museum is open.

It often carries a slight sense of distance: I’m not personally guaranteeing this is true.

A very common learner question. Yes, the basic statement is:

• Muzej je otvoren. = The museum is open.

But Croatian has a rule for clitics like je: they usually go in second position in the sentence or clause.

So when navodno comes first, je moves right after it:

• Navodno je muzej otvoren.

This is very natural Croatian word order.

So the sentence is not strange or inverted in a dramatic way; it is mostly following the normal second-position clitic rule.

Je is the 3rd person singular present form of biti (to be):

• ja sam = I am
• ti si = you are
• on/ona/ono je = he/she/it is

So in this sentence:

• je = is

Because muzej is singular, je is singular too.

Otvoren agrees with muzej.

Since muzej is:

• masculine
• singular
• the subject of the sentence

the predicate adjective also appears in the masculine singular form:

• masculine singular: otvoren
• feminine singular: otvorena
• neuter singular: otvoreno
• masculine plural: otvoreni

Examples:

• Muzej je otvoren. = The museum is open.
• Galerija je otvorena. = The gallery is open.
• Kazalište je otvoreno. = The theater is open.

Here, otvoren is best understood as open in the adjectival sense.

So:

• muzej je otvoren = the museum is open

In some contexts, forms like otvoren can also relate to the verb otvoriti (to open) and behave like a participle, but in this sentence the natural meaning is a state: the museum is currently open.

English has a similar difference:

• The door is open = state
• The door was opened = action

Here Croatian is expressing the state.

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

The dictionary form is:

• muzej = museum

In this sentence:

• muzej = the museum / a museum, depending on context

Croatian does not use articles, so the same noun form can correspond to English the museum or a museum.

Because Croatian has no articles.

English distinguishes:

• a museum
• the museum

Croatian usually does not mark that difference with a separate word. Instead, the meaning comes from context.

So:

• muzej can mean a museum or the museum

In Navodno je muzej otvoren, English will usually translate it as the museum is open, because that is what sounds most natural in context.

Yes, but the nuance or style may change a little.

Possible versions include:

• Navodno je muzej otvoren.
  Very natural. Focuses first on apparently / reportedly.

• Muzej je navodno otvoren.
  Also natural. The subject comes first, then navodno modifies the statement.

Both usually mean the same thing:

• Apparently, the museum is open.

A version like Muzej je otvoren navodno sounds less natural in neutral everyday Croatian.

So as a learner, the two most useful patterns are:

• Navodno je muzej otvoren.
• Muzej je navodno otvoren.

Often, yes — at least a little.

It can simply mean reportedly in a neutral sense, but it also often suggests:

• this is what people say
• I’m not confirming it myself
• sometimes even I’m not fully convinced

So the tone depends on context and intonation.

For example:

• neutral: Navodno je muzej otvoren, ali provjeri radno vrijeme.
  = Apparently the museum is open, but check the opening hours.
• more skeptical: Navodno je muzej otvoren, ali vrata su zaključana.
  = The museum is supposedly open, but the doors are locked.

Not normally in the most natural reading of this sentence.

Navodno je muzej otvoren is most naturally understood as:

• Apparently, the museum is open

If you want the idea of was opened, Croatian would usually make that clearer through context or by using a different structure, for example:

• Muzej je otvoren jučer. = The museum was opened yesterday. / The museum opened yesterday.
  But even this can be ambiguous without context.
• Jučer je otvoren muzej. = Yesterday a/the museum was opened.
  This sounds more event-like.

So in your original sentence, the default interpretation is the state: the museum is open.

Yes. Croatian normally does not need subject pronouns unless they are emphasized.

The subject here is not a pronoun anyway; it is the noun muzej. So the sentence is fully complete:

• Navodno je muzej otvoren.

Even when Croatian uses verbs without an explicit pronoun, that is often perfectly normal because the verb form already shows the person and number.