Motlyset er kraftig.

Because Norwegian usually writes compound nouns as a single word.
Here, motlys is a compound made from:

• mot = against / toward
• lys = light

So motlys is a fixed noun meaning backlight, glare, or light coming from the front/against you depending on context. When it becomes definite, you get motlyset.

The -et is the definite ending for a singular neuter noun in Bokmål.

So the pattern is:

• et motlys = a backlight / a glare
• motlyset = the backlight / the glare

This is very common in Norwegian. Instead of usually adding a separate word like English the, Norwegian often adds the definite article to the end of the noun.

Motlys is a neuter noun, which is why you say:

• et motlys
• motlyset

That neuter gender also helps explain other grammar around the noun.

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

So:

• er = is / are / am depending on the subject

In this sentence, Motlyset er kraftig, it simply means the backlight is strong/intense.

This is a very common learner question.

Normally, predicative adjectives in Norwegian often agree with the noun:

• lyset er sterkt = the light is strong

But kraftig belongs to a group of adjectives that usually do not add -t in the neuter singular, especially adjectives ending in -ig.

So you get:

• et kraftig lys
• lyset er kraftig

not kraftigt

The plural/definite form would be:

• kraftige

So:

• et kraftig lys
• flere kraftige lys

Often yes, but kraftig can also mean:

• powerful
• intense
• heavy in some contexts

In Motlyset er kraftig, it usually means the backlight is strong or intense, not physically strong like a person.

So the exact English wording depends on context, but strong is a very natural basic translation.

This is the normal Norwegian word order for a simple statement:

• subject + verb + complement

So:

• Motlyset = subject
• er = verb
• kraftig = adjective/complement

This matches normal English word order quite closely:

• The backlight is strong.

Yes, but it is not exactly the same structure.

• Motlyset er kraftig = The backlight is strong
• Det er kraftig motlys = There is strong backlight / It is very backlit

The first sentence talks about the backlight as a specific thing.
The second presents the situation more generally.

Both can be natural, depending on what you want to emphasize.

Because in Norwegian, definiteness is often shown by attaching an ending to the noun.

Compare:

• et lys = a light
• lyset = the light

So in motlyset, the idea of the is already built into the noun. That is why you do not add another separate article in a basic sentence like this.

Yes, especially in photography, film, driving, and everyday situations where light shines toward your eyes.

For example, Norwegian speakers might use it when:

• taking a photo into the sun
• talking about glare while driving
• describing a person standing with bright light behind them

So it is a useful practical vocabulary word.

A simple learner-friendly approximation is:

• MOOT-ly-seh

A few pronunciation notes:

• mot sounds roughly like moht
• lys has the Norwegian y, which is not like the English y in yes. It is a rounded vowel, similar to the u in French tu or German ü
• the final -et in motlyset is usually pronounced more like -e or -eh in everyday speech, not a strong English et

If you cannot say the Norwegian y yet, that is normal. It takes practice.

Yes. Depending on context, motlys/motlyset can be translated as:

• backlight
• glare
• light shining toward you
• backlighting

English chooses different words depending on the situation, but Norwegian can use motlys for all of these related ideas.

Sometimes yes.

• Motlyset er sterkt = the backlight is strong
• Motlyset er kraftig = the backlight is powerful/intense

The difference is small, and in many contexts both are possible.
Kraftig can sound a bit more like intense or powerful, while sterkt is the more direct match for strong.

So both may be correct, but kraftig is a natural choice when talking about light that feels forceful or intense.