Han har dårlig samvittighet.

Because ha dårlig samvittighet is the normal Norwegian expression for to feel guilty or to have a guilty conscience.

So Norwegian says:

• Han har dårlig samvittighet. = He feels guilty / He has a bad conscience.

Using er would not work here:

• Han er dårlig samvittighet is incorrect.

This is one of those cases where Norwegian and English structure the idea differently.

Samvittighet means conscience.

It refers to your inner sense of right and wrong. In this sentence, dårlig samvittighet means something like:

• a guilty conscience
• feeling bad about something you did or failed to do

So the sentence is not saying that his conscience is literally poor in quality. It means he feels morally uneasy or guilty.

Because ha dårlig samvittighet is a very common fixed expression in Norwegian.

Norwegian often leaves out the article in set phrases with abstract nouns, especially after verbs like ha. So:

• Han har dårlig samvittighet. = natural, idiomatic

If you added an article:

• Han har en dårlig samvittighet.

that can sound less idiomatic in the usual feels guilty sense. It is not impossible, but the article-free version is the normal one when talking about guilt in general.

Because dårlig is here in its basic adjective form, used before a singular indefinite noun.

The noun is:

• en samvittighet = a conscience

That is a common-gender singular noun, so the adjective normally stays in the basic form:

• dårlig samvittighet

Compare:

• en dårlig idé = a bad idea
• en dårlig vane = a bad habit

You would see other forms in other contexts, for example:

• et dårlig råd = a bad piece of advice
• dårlige vaner = bad habits

It is normally a common-gender noun in Bokmål:

• en samvittighet
• samvittigheten

That is why the adjective appears as dårlig and not the neuter form dårligt.

It is both understandable literally and very idiomatic.

Literally, it means:

• He has bad conscience

But in real English, the most natural translation is usually:

• He feels guilty
• He has a guilty conscience

So if you are learning it, it is best to remember ha dårlig samvittighet as a whole expression.

Yes, but the reason is not stated in the sentence itself.

Han har dårlig samvittighet. simply says that he feels guilty. The listener may already know why, or the reason may come later.

For example:

• Han har dårlig samvittighet for det han sa.
  He feels guilty about what he said.

• Hun har dårlig samvittighet fordi hun ikke ringte.
  She feels guilty because she didn’t call.

So the basic sentence can stand alone, but it often invites the question about what?

You negate it by putting ikke after the verb:

• Han har ikke dårlig samvittighet. = He does not feel guilty.

This follows standard Norwegian word order in main clauses:

• subject + verb + ikke
  • rest

So:

• Han
  • har
    • ikke
      • dårlig samvittighet

In a yes/no question, the verb comes first:

• Har han dårlig samvittighet? = Does he feel guilty?

This is very common Norwegian word order for questions:

• Har du tid? = Do you have time?
• Er hun hjemme? = Is she at home?

So the sentence simply becomes inverted.

A rough guide is:

• dårlig ≈ DOAR-lee
  with å sounding like the vowel in British law for many learners

More specifically:

• då- has the Norwegian å sound
• -rlig can be tricky because of the Norwegian r
  • l combination, and many speakers pronounce it in a way that may sound a bit reduced to learners

You do not need perfect pronunciation right away, but make sure:

• å is not pronounced like English a in bad
• the word has stress on the first syllable: DÅR-lig

A rough learner-friendly approximation is:

• SAM-vit-ti-het

Stress is on the first syllable:

• SAM-vittighet

A few helpful points:

• tt makes the preceding vowel short
• the final -het sounds like heht, not English hate
• the whole word is longer than its English equivalent conscience, so it may take practice

If you say it slowly at first, that is completely fine:

• sam-vit-ti-het

Sometimes yes, but not always.

Han har dårlig samvittighet focuses on the feeling of guilt, not necessarily legal or factual guilt. So:

• He feels guilty is usually safest
• He has a guilty conscience is also very accurate
• He is guilty can be too strong or mean he actually committed the wrongdoing

For example, someone can ha dårlig samvittighet even if they only forgot to call a friend. That does not mean they are guilty in a legal or dramatic sense.

Yes. Norwegian uses ha in many expressions that are best learned as whole chunks. For example:

• ha rett = be right
• ha lyst = feel like / want to
• ha behov for = need
• ha det travelt = be busy / be in a hurry
• ha dårlig tid = be short of time

So ha dårlig samvittighet is part of a larger pattern: Norwegian often says have where English might prefer be or some other structure.