Bruktbilen er god, om enn dyr.

Bruktbilen is one word because Norwegian often makes compound nouns.

• bruktbil = used car
• bruktbilen = the used car

The ending -en is the definite singular ending for many masculine/feminine/common-gender nouns.

So:

• en bruktbil = a used car
• bruktbilen = the used car

Both are possible in Norwegian, but they are not exactly the same in feel.

• bruktbilen uses the compound noun bruktbil, which is the normal dictionary-style word for used car
• den brukte bilen literally means the used car too, but it is built with an adjective + noun structure

In many cases, Norwegian prefers the compound noun when it is a fixed concept:

• bruktbil = used car
• rødvin = red wine
• sykehus = hospital

So bruktbilen sounds very natural here.

Om enn is a fixed expression meaning something like:

• although
• even if
• albeit

In this sentence, it introduces a concession: the car is good, but there is still a negative point.

So:

• Bruktbilen er god, om enn dyr. = The used car is good, albeit expensive.

This expression is a bit more formal or literary than the most everyday alternatives.

It is understandable and perfectly correct, but it is a little formal or written in tone.

In everyday speech, many Norwegians would more often say something like:

• Bruktbilen er god, selv om den er dyr.
• Bruktbilen er god, men dyr.

So om enn is useful to know, but it is not the most casual everyday phrasing.

Because the subject bruktbilen is a common-gender singular noun.

When an adjective is used after er as a predicative adjective, it still agrees with the noun in gender and number:

• Bilen er god. = common gender singular
• Huset er godt. = neuter singular
• Bilene er gode. = plural

Since bil is not neuter, the correct form is god.

This is a very common question.

Even though bruktbilen is definite, the adjective after er does not take the definite form. That is because dyr here is a predicative adjective, not an adjective placed before the noun.

Compare:

• den dyre bruktbilen = the expensive used car
  
  • here the adjective is attributive, before the noun, so it becomes dyre
• bruktbilen er dyr = the used car is expensive
  
  • here the adjective is predicative, after er, so it stays dyr

So the definiteness of the noun does not make you say dyre after er.

Yes, in a way there is an implied clause.

Om enn dyr is a shortened version of something like:

• om den enn er dyr
• selv om den er dyr

In this sentence, Norwegian leaves out material that is understood from context. The full idea is:

• The used car is good, although it is expensive.

So dyr stands alone because the rest is understood.

No. It is often followed by a short phrase, and adjectives are very common, but it is not limited to that.

For example, you may see structures like:

• god, om enn dyr = good, albeit expensive
• enkel, om enn litt gammeldags = simple, though a bit old-fashioned

The important thing is that om enn introduces a concession. In practice, it often appears before a concise descriptive phrase.

The comma helps mark om enn dyr as a kind of inserted concessive comment.

• Bruktbilen er god, om enn dyr.

This is the most natural written punctuation for this kind of sentence. The part after the comma adds a qualification:

• it is good
• but there is a reservation: it is expensive

So the comma reflects the pause and the parenthetical feel of the phrase.

Yes. That is a very good natural English translation.

Depending on style, possible translations include:

• The used car is good, albeit expensive.
• The used car is good, though expensive.
• The used car is good, if somewhat expensive.

They all capture the same basic idea.

Yes, both can be used, but they are not always identical in feel.

• god can mean good in a broad sense
• bra is also very common and often sounds a bit more everyday in many contexts

So these are both possible:

• Bruktbilen er god, om enn dyr.
• Bruktbilen er bra, om enn dyr.

The original sentence is perfectly grammatical and natural, but god may sound a little more deliberate or evaluative here.

The structure is:

• Bruktbilen = subject
• er = verb
• god = predicative adjective
• om enn dyr = concessive phrase

So the core sentence is:

• Bruktbilen er god.

Then Norwegian adds a qualification:

• om enn dyr

That gives the full meaning:

• The used car is good, although expensive.

Yes. A more expanded version would be:

• Bruktbilen er god, selv om den er dyr.

That is less compact and more conversational. The original version with om enn is shorter and more elegant in style, but the meaning is essentially the same.