De asielhond is zindelijk.

Asielhond is a compound noun: asiel + hond.

• asiel can mean shelter in this context, especially an animal shelter
• hond means dog

So asielhond means shelter dog or dog from a shelter.

Dutch very often combines words into one compound where English would use two words or a longer phrase.

Because hond is a de-word in Dutch, and the whole compound keeps the gender of the final noun.

The important part is the last part of the compound:

• de hond = the dog
• therefore de asielhond = the shelter dog

This is a very useful rule in Dutch: in compound nouns, the last word usually determines the article.

Because zindelijk is being used as a predicate adjective after the verb is.

Compare:

• de zindelijke hond = the house-trained dog
  
  • here the adjective comes before the noun, so it usually takes -e
• de hond is zindelijk = the dog is house-trained
  
  • here the adjective comes after is, so it normally has no -e

So in De asielhond is zindelijk, zindelijk stays in its basic form.

For animals, zindelijk usually means house-trained, toilet-trained, or not having accidents indoors.

It can also be used more generally to mean clean or hygienic, but with pets the meaning is usually specifically about toilet habits.

So in this sentence, it most likely means the dog is properly house-trained.

Yes. It can be used for people, especially young children.

For example:

• Een kind is al zindelijk. = A child is already toilet-trained.

So the word can be used for both humans and animals, depending on context.

The sentence has a very basic Dutch pattern:

• De asielhond = subject
• is = verb
• zindelijk = predicate adjective / complement

So the structure is:

Subject + verb + adjective

This is very similar to English:

The shelter dog + is + house-trained

Dutch main clauses normally follow the V2 rule, which means the finite verb comes in the second position.

In this sentence:

• first element: De asielhond
• second element: is

So De asielhond is zindelijk is exactly what you would expect in a normal Dutch statement.

Yes, absolutely.

That means:

• De hond uit het asiel = The dog from the shelter

This version uses a phrase instead of a compound noun. Both are grammatical.

The difference is mainly style:

• de asielhond = compact, noun-compound style
• de hond uit het asiel = more explicit, more literally the dog from the shelter

A rough English-friendly guide:

• asielhond ≈ ah-SEEL-hont
• zindelijk ≈ ZIN-duh-lik or ZIN-duh-lək

A few notes:

• ie in asiel sounds like ee in see
• Dutch z sounds like the z in zoo
• the final d in hond is often pronounced more like a t sound at the end
• the ij in zindelijk is a typical Dutch vowel sound, not exactly the same as English i

Not always. The basic word asiel can mean asylum, but in everyday Dutch it is also commonly used for an animal shelter, especially in combinations like:

• dierenasiel = animal shelter
• asielhond = shelter dog
• asielkat = shelter cat

So the exact meaning depends on context. Here, it clearly refers to an animal shelter.