Personen var grusom.

Because personen is the definite singular form of person.

In Norwegian, nouns usually add the definite article to the end of the word:

• en person = a person
• personen = the person

So Personen var grusom means The person was cruel/awful, not A person was cruel/awful.

In Norwegian, the definite article is often attached to the noun as a suffix instead of being a separate word.

So where English says:

• the person

Norwegian says:

• personen

This is very normal in Norwegian. The ending -en is doing the job of the here.

Var is the past tense of å være, which means to be.

Some common forms are:

• er = am / is / are
• var = was / were
• har vært = have been / has been

So in Personen var grusom, var tells you the sentence is in the past: was.

Here grusom is a predicate adjective, meaning it comes after the verb var and describes the subject.

With many adjectives in Norwegian, the form changes depending on gender/number when used before a noun, but after to be it still has to agree with the subject.

Compare:

• en grusom person = a cruel person
• et grusomt menneske = a cruel human being
• grusomme personer = cruel people

But in your sentence, the subject is personen, and person is a common-gender singular noun, so grusom is the correct form:

• Personen var grusom

If the subject were neuter, you would use grusomt:

• Barnet var grusomt = The child was cruel

And if plural:

• Personene var grusomme = The people were cruel

Yes, in this sentence it is very similar to English:

• Personen = subject
• var = verb
• grusom = adjective/complement

So it follows the pattern:

Subject + verb + description

That is why it feels very familiar to an English speaker: The person was cruel → Personen var grusom

Yes. Depending on context, grusom can mean things like:

• cruel
• awful
• terrible
• horrible

When talking about a person, it often suggests that the person was very nasty, harsh, or morally bad. The exact English translation depends on context, but grammatically the Norwegian sentence stays the same.

A rough pronunciation guide for an English speaker is:

pehr-SOO-nen var GROO-som

A few notes:

• r in Norwegian is usually not like a strong English r
• u in grusom is not exactly like English oo, but groo-som is a helpful approximation
• the stress is usually on the first syllable of grusom

Pronunciation varies somewhat by dialect, but this approximation will help you get started.

Yes, you could. Den personen var grusom means That person was cruel or That person was awful.

The difference is:

• Personen var grusom = The person was cruel
• Den personen var grusom = That person was cruel

So adding den makes it more specific or contrastive, like pointing someone out.

In modern Norwegian Bokmål, person is normally treated as a common gender noun, so the indefinite article is en:

• en person
• personen

Common gender in Bokmål covers what used to be masculine and, in many cases, feminine usage. So for learning purposes, it is safest to remember:

• person → en person
• definite form → personen

It is clearly natural in Bokmål.

In Nynorsk, you would more typically see:

• Personen var grufull
• or another adjective depending on context

Also, the definite form and vocabulary choices can differ in Nynorsk. So if you are studying Bokmål, Personen var grusom is perfectly fine.