Málverkið er gamalt.

It is the definite article attached to the noun. So:

• málverk = painting
• málverkið = the painting

Icelandic often expresses the by adding an ending to the noun instead of using a separate word.

The dictionary form is málverk. When you look up a noun, you usually remove the definite ending first:

• málverkið → málverk

It is neuter. You can tell from the sentence because the adjective is gamalt, which is the neuter singular form of old.

In dictionaries, you will usually see this marked as málverk (n.).

Er is the 3rd-person singular present form of að vera, which means to be.

So here it simply means is.

Because Icelandic adjectives must agree with the noun in gender, number, and usually case.

Since málverkið is neuter singular, the adjective must also be neuter singular:

• gamall = masculine singular
• gömul = feminine singular
• gamalt = neuter singular

So gamalt is the correct form here.

Look it up under gamall.

Icelandic adjectives are usually listed in the masculine singular nominative form. Sometimes dictionaries also show the three basic singular forms together:

• gamall, gömul, gamalt

Because gamalt is being used predicatively: it comes after er and tells you something about the subject.

Predicative adjectives normally use the strong form, so you get:

• Málverkið er gamalt = The painting is old

The form gamla is a weak form, typically used when the adjective stands directly with a definite noun:

• gamla málverkið = the old painting

So these are different structures:

• Málverkið er gamalt = complete sentence
• gamla málverkið = noun phrase

It is nominative, because it is the subject of the sentence.

With að vera, the subject is nominative, and the predicate adjective matches it, so gamalt is also nominative singular neuter.

Because here the adjective is not inside the noun phrase. It is a predicate adjective after er:

• Málverkið er gamalt = The painting is old

If you put the adjective directly before the noun, you get a different kind of expression:

• gamalt málverk = an old painting
• gamla málverkið = the old painting

So word position changes the structure.

Icelandic does not have a separate word for a/an. You normally use the noun without the definite ending:

• Málverk er gamalt

Depending on context, that can mean A painting is old or something more general.

If you want to make one explicit, you can say:

• Eitt málverk er gamalt = One/A painting is old

It becomes:

• Málverkin eru gömul.

Breakdown:

• málverkin = the paintings
• eru = are
• gömul = old in the neuter plural form