Veggurinn er ljótur.

The base form is veggur, which means wall.

Veggurinn breaks down like this:

• veggur = wall
• -inn = the attached definite article, meaning the

So veggurinn means the wall.

In Icelandic, the is usually not a separate word like it is in English. Instead, it is attached to the end of the noun.

So:

• veggur = wall
• veggurinn = the wall

This attached the is very common in Icelandic.

Er means is.

It is the 3rd person singular present tense form of the verb vera, which means to be.

So:

• ég er = I am
• þú ert = you are
• hann/hún/það er = he/she/it is

In Veggurinn er ljótur, er links the subject and the description, just like is in English.

Because ljótur has to agree with veggurinn.

The noun veggur is:

• masculine
• singular
• nominative

So the adjective also appears in the masculine singular nominative form:

• ljótur = masculine singular nominative

Other forms would be used with different genders:

• ljótur = masculine
• ljót = feminine
• ljótt = neuter

So if the noun changes, the adjective changes too.

Yes. Veggur is a masculine noun.

That matters because Icelandic adjectives must match the noun in:

• gender
• number
• case

That is why the sentence uses ljótur and not a feminine or neuter form.

It is in the nominative case.

That is because veggurinn is the subject of the sentence — it is the thing being described.

In a simple sentence like The wall is ugly, the subject is normally nominative in Icelandic.

Because this sentence uses a predicate adjective.

The structure is:

• noun + er + adjective

So:

• Veggurinn er ljótur = The wall is ugly

This is different from putting the adjective directly before the noun:

• ljótur veggur = an ugly wall
• ljóti veggurinn = the ugly wall

So in your sentence, ljótur comes after er because it is part of the predicate, not directly attached before the noun.

Good question. In Icelandic, adjectives often use the weak form before a definite noun:

• ljóti veggurinn = the ugly wall

But after vera (to be), predicate adjectives normally use the strong form:

• Veggurinn er ljótur = The wall is ugly

So even though veggurinn is definite, ljótur is correct here because it is a predicate adjective, not an attributive adjective placed before the noun.

Yes. This is the normal, basic word order for a statement:

• Veggurinn = subject
• er = verb
• ljótur = complement/adjective

So the pattern is basically:

• Subject + Verb + Description

That is the most neutral way to say it.

You would say:

• Veggur er ljótur.

That means A wall is ugly or Wall is ugly, depending on context.

Icelandic does not have a separate indefinite article like English a/an, so the bare noun can often have that meaning.

The plural would be:

• Veggirnir eru ljótir. = The walls are ugly.

Here several things change:

• veggurinn → veggirnir
• er → eru
• ljótur → ljótir

Again, the adjective changes to match the noun in number and gender.

They mean different kinds of things grammatically:

• Veggurinn er ljótur = The wall is ugly
  
  • a complete sentence
• Ljóti veggurinn = the ugly wall
  
  • just a noun phrase, not a full sentence

So:

• use Veggurinn er ljótur when you want to make a statement
• use ljóti veggurinn when you are talking about the ugly wall as a thing

The main things are:

1. The definite article is attached to the noun

   • veggur → veggurinn

2. The verb is a form of vera

   • er = is

3. The adjective agrees with the noun

   • veggurinn is masculine singular nominative
   • so the adjective is ljótur

4. Predicate adjectives come after the verb

   • Veggurinn er ljótur
   • not Veggurinn ljótur er

It is a short sentence, but it shows several very important Icelandic patterns.