Leiren er fuktig.

Because Norwegian usually puts the definite article at the end of the noun.

• leir = camp
• en leir = a camp
• leiren = the camp

So Leiren er fuktig means The camp is damp/moist. If you said just leir, it would sound incomplete in a normal sentence like this.

Leir is a common-gender noun in Bokmål, so it takes en in the indefinite singular.

Useful forms:

• en leir = a camp
• leiren = the camp
• leirer = camps
• leirene = the camps

So this sentence uses the definite singular form.

Er is the present tense of å være = to be.

So:

• jeg er = I am
• du er = you are
• han/hun er = he/she is
• de er = they are

Unlike English, Norwegian does not change the present-tense form of å være depending on the subject. It is always er in the present.

Here, fuktig is a predicative adjective: it comes after er and describes the subject.

In Leiren er fuktig, the subject is singular, so fuktig is the correct form.

A useful comparison:

• Leiren er fuktig = The camp is damp
• Leirene er fuktige = The camps are damp

So the plural form is fuktige.

Also, adjectives ending in -ig often stay the same in singular, so you do not add an extra -t here.

Fuktig usually means something like:

• damp
• moist
• sometimes humid, depending on context

With something like a camp, ground, tent, or air in a camp, damp is often the most natural English idea.

So fuktig is less extreme than soaking wet. It suggests there is moisture, but not necessarily that everything is dripping.

Yes, but the meaning changes a bit.

• fuktig = damp / moist
• våt = wet

So:

• Leiren er fuktig suggests the camp is somewhat damp.
• Leiren er våt sounds stronger: the camp is wet.

In many situations, fuktig is the more natural choice if you mean there is moisture in the air, ground, or surroundings.

You would say den fuktige leiren.

This is a very common Norwegian pattern called double definiteness:

• den = the
• fuktige = damp
• leiren = the camp

So:

• Leiren er fuktig = The camp is damp
• den fuktige leiren = the damp camp

Notice that when the adjective comes before a definite noun, Norwegian usually needs both:

1. a definite word like den
2. the definite ending on the noun

This sentence uses the normal main-clause order:

subject + verb + adjective

• Leiren = subject
• er = verb
• fuktig = description

But Norwegian main clauses follow the V2 rule, which means the verb is usually in the second position.

For example:

• I dag er leiren fuktig. = Today the camp is damp.

And if you want to make it a yes/no question, you usually put the verb first:

• Er leiren fuktig? = Is the camp damp?

Normally, no.

If you mean the camp, you need leiren.

If you mean a camp, you would usually say en leir:

• En leir er fuktig. = A camp is damp.

A bare noun like leir without an article is not usually used this way in ordinary Norwegian.

A rough English-friendly guide would be:

• leiren ≈ LY-ren or LAIR-en depending on dialect
• er = a short form of is / are
• fuktig ≈ FOOK-tig, but with a Norwegian u sound that is not exactly the same as English oo

A few pronunciation notes:

• ei in leiren is a diphthong, often somewhat like the vowel in eye
• r varies by dialect
• g at the end of fuktig is usually pronounced

So even if your pronunciation is not perfect, aiming for something like LY-ren er FOOK-tig will get you close enough to be understood.

In the plural, both the noun and the adjective change:

• Leirene er fuktige. = The camps are damp.

Compare:

• leiren = the camp
• leirene = the camps
• fuktig = damp (singular here)
• fuktige = damp (plural)

This is a useful pattern to remember for many Norwegian sentences.