Fuktighetsmåleren avslører overvanning.

The ending -en is the definite singular ending for many masculine nouns in Norwegian.

So:

• en fuktighetsmåler = a moisture meter
• fuktighetsmåleren = the moisture meter

That means the sentence is talking about a specific moisture meter, not just any moisture meter.

It is a compound noun plus a definite ending:

• fuktighet = moisture
• måler = meter / gauge / measurer
• fuktighetsmåler = moisture meter
• fuktighetsmåleren = the moisture meter

So Norwegian often packs a lot into one long word where English would use multiple words.

That -s- is a linking sound used in many Norwegian compound nouns.

Here:

• fuktighet
  • måler → fuktighetsmåler

You cannot always predict it perfectly from logic alone; it is often just part of how the compound is normally formed. The important thing is to learn the whole compound as a vocabulary item.

Other compounds in Norwegian also use a linking -s-, while some do not.

Avslører is the present tense of avsløre.

• å avsløre = to reveal / uncover / expose
• avslører = reveals / is revealing

In this sentence, it means something like:

• reveals
• detects
• shows

depending on context.

Norwegian present tense is often formed by adding -r to the infinitive:

• å avsløre → avslører

In literal dictionary terms, avsløre often means reveal, uncover, or expose.

But in a sentence like Fuktighetsmåleren avslører overvanning, it can sound natural in English as:

• The moisture meter reveals overwatering
• The moisture meter detects overwatering
• The moisture meter shows that there has been overwatering

So yes, in context it can overlap with detect or show, even if the core idea is still reveal.

Because it is a single noun:

• over- = over-, excessive
• vanning = watering
• overvanning = overwatering

Norwegian, like English, often forms nouns this way. Since it is a noun here, it is written as one word.

Here overvanning is being used as an uncountable or general noun, similar to English overwatering.

So Norwegian does not need an article:

• Fuktighetsmåleren avslører overvanning.
• The moisture meter reveals overwatering.

If you made it definite, it would become more specific:

• overvanningen = the overwatering

But in this sentence, the general form overvanning is the natural choice.

The sentence has normal Norwegian subject–verb–object order:

• Fuktighetsmåleren = subject
• avslører = verb
• overvanning = object

So:

• Fuktighetsmåleren / avslører / overvanning
• The moisture meter / reveals / overwatering

This is a very straightforward main-clause structure.

It would be:

• En fuktighetsmåler avslører overvanning.

That means:

• A moisture meter reveals overwatering.

Compare:

• En fuktighetsmåler = a moisture meter
• Fuktighetsmåleren = the moisture meter

So the original sentence is definite, while this version is indefinite.

They are important sounds in Norwegian:

• ø in avslører is roughly like the vowel in French peur or German schön. English does not have an exact match.
• å in måleren is roughly like the vowel in British English law or more, though not exactly the same.

Very roughly:

• måler sounds something like MOH-ler
• avslører sounds roughly like ahv-SLUR-er, but with a true Norwegian ø sound, not an English u

The exact pronunciation depends somewhat on dialect, but learning ø and å early is very helpful.

The usual forms are:

• en fuktighetsmåler = a moisture meter
• fuktighetsmåleren = the moisture meter
• fuktighetsmålere = moisture meters
• fuktighetsmålerne = the moisture meters

This is a useful pattern for many masculine nouns in Norwegian:

• singular indefinite: en ...
• singular definite: ...en
• plural indefinite: ...e
• plural definite: ...ene / ...ne

Here the plural is fuktighetsmålere.