Mannen er naken.

Because mannen means the man, while mann means man or a man.

In Norwegian, the definite article is usually attached to the end of the noun instead of being a separate word:

• mann = man
• en mann = a man
• mannen = the man

So Mannen er naken means The man is naked, not just Man is naked.

Norwegian usually puts the at the end of the noun as a suffix.

So instead of a separate word like English the man, Norwegian often uses:

• mannen = the man
• kvinnen = the woman
• barnet = the child

That -en ending in mannen is doing the job of English the.

Er means is / am / are, depending on context. It is the present tense of å være, which means to be.

Examples:

• Jeg er = I am
• du er = you are
• mannen er = the man is

So in this sentence, er simply means is.

Because naken here is a predicate adjective: it comes after er and describes the subject.

In Norwegian, predicate adjectives usually agree with gender and number, but not with definiteness in the same way attributive adjectives do.

So you get:

• Mannen er naken = The man is naked
• Kvinnen er naken = The woman is naked
• Barnet er nakent = The child is naked
• Mennene er nakne = The men are naked

Notice that:

• common gender singular: naken
• neuter singular: nakent
• plural: nakne

So mannen is definite, but that does not force naken to become a definite adjective form here.

The adjective changes to match the subject.

Examples:

• Kvinnen er naken = The woman is naked
• Barnet er nakent = The child is naked
• Mennene er nakne = The men are naked
• Barna er nakne = The children are naked

This is a good pattern to remember for adjectives after er:

• common gender singular: basic form
• neuter singular: often -t
• plural: often -e

In this simple statement, yes. It is:

subject + verb + adjective

So:

• Mannen = subject
• er = verb
• naken = adjective

This is very similar to English The man is naked.

However, Norwegian is a verb-second language, so in other sentence types the verb still has to stay in second position:

• Er mannen naken? = Is the man naked?
• I dag er mannen naken. = Today the man is naked.

Yes, sometimes mannen can mean the husband, depending on context.

The noun mann can mean:

• man
• husband in some contexts

So Mannen er naken could theoretically mean The husband is naked if the surrounding context makes that clear.

But with no extra context, most learners should read it simply as The man is naked.

Yes, that is grammatically correct, but the meaning changes.

• Mannen er naken = The man is naked
  A specific man, probably already known from the context.

• En mann er naken = A man is naked
  An unspecified man.

So the choice between mannen and en mann depends on whether you mean the specific man or just a man.

A rough Standard East Norwegian pronunciation is:

MAHN-ən er NAH-kən

Very roughly:

• mannen: the first part sounds a bit like man with a short vowel, then a weak -en
• er: often a short sound like ær
• naken: roughly NAH-kən

A few helpful notes:

• the double nn in mannen makes the preceding vowel short
• the e in endings like -en is often weak, like the a in English sofa
• pronunciation varies by dialect, sometimes quite a lot

Naken is a normal, standard word. It means naked and is not inherently rude.

Depending on context, English might translate it as:

• naked
• nude

It is a straightforward descriptive adjective. Whether the sentence feels awkward or funny depends more on the situation than on the word itself.