Det lyder som en god idé.

In this sentence, det works a lot like English it in It sounds like a good idea. It does not have to point to a specific physical thing. It can refer generally to what was just said, suggested, or discussed.

So if someone proposes a plan, you can reply with Det lyder som en god idé.

Lyder is the present tense of at lyde, which means to sound.

So:

• at lyde = to sound
• lyder = sounds

This is the same kind of meaning as English sounds in That sounds good or That sounds interesting.

After lyde, Danish often uses som when you are saying what something seems or sounds like.

So:

• Det lyder som en god idé = It sounds like a good idea

You normally cannot leave som out here. Lyde som is the standard pattern before a noun phrase like en god idé.

Because idé is a common gender noun in Danish, so it takes en, not et.

That also affects the adjective:

• en god idé
• not et godt idé

Compare with a neuter noun:

• et godt forslag = a good suggestion

So the form of the article and adjective depends on the noun’s gender.

Because Danish uses the structure lyder som directly.

In English, you say:

• It sounds like a good idea

You do not say:

• It sounds is a good idea

Danish works the same way here. Som en god idé is the complement of lyder.

The difference is mostly about how direct or certain you sound.

• Det lyder som en god idé is a bit softer and more tentative. It means that, based on what you have heard, it seems like a good idea.
• Det er en god idé is more direct and definite. You are stating clearly that it is a good idea.

So Det lyder som en god idé is often a polite, natural response in conversation.

Yes, but it means something slightly different.

• Det lyder godt = That sounds good
• Det lyder som en god idé = That sounds like a good idea

The first one is shorter and more general. The second one specifically labels the suggestion as a good idea.

Because Danish main clauses usually follow the verb-second rule.

In a normal statement, if the subject comes first, the finite verb comes second:

• Det
  • lyder
    • som en god idé

If some other element comes first, the verb still stays in second position:

• For mig lyder det som en god idé = To me, it sounds like a good idea

This verb-second pattern is very important in Danish word order.

The stress is on the second syllable: i-DÉ.

That is one reason the accent is written: idé helps show where the stress goes. English speakers often want to stress the first syllable, but in Danish the stress is at the end.

So try to think of it as:

• i-DÉ

not

• I-de

Yes, very natural. It is a common, neutral, everyday phrase.

You can use it when reacting positively to a suggestion, for example in conversation with friends, family, classmates, or coworkers. It sounds friendly and normal, and often a little less strong than a direct statement like Det er en god idé.