Flokkunarleiðbeiningarnar eru skýrar.

It is a compound noun:

• flokkunar- = of classification / for classification
• leiðbeiningar = instructions, guidelines
• -nar = the definite article ending here, giving the

So flokkunarleiðbeiningarnar is literally something like the classification guidelines or the sorting instructions.

Icelandic makes compounds very freely, much more than English does, so long words like this are very normal.

Because Icelandic usually adds the definite article to the end of the noun instead of using a separate word.

So:

• leiðbeiningar = guidelines / instructions
• leiðbeiningarnar = the guidelines / the instructions

In this sentence, that ending is attached to the whole compound noun, giving flokkunarleiðbeiningarnar.

This is a very common feature of Icelandic compounds. The first noun often appears in a linking form that is identical to the genitive form.

Here:

• flokkun = classification
• flokkunar = genitive singular, of classification

So flokkunarleiðbeiningar is literally something like guidelines of classification, which English would normally express as classification guidelines.

Because the subject is plural.

• er = is
• eru = are

The subject flokkunarleiðbeiningarnar is plural, so Icelandic uses the plural form of vera (to be):

• Flokkunarleiðbeiningarnar eru ... = The classification guidelines are ...

Because the adjective has to agree with the noun in number, gender, and case.

The subject flokkunarleiðbeiningarnar is:

• plural
• feminine
• nominative

So the adjective skýr (clear) appears in the matching form skýrar.

A very important point: after vera (to be), Icelandic uses the adjective in a predicate position, and predicate adjectives normally take the strong form, even if the noun is definite. That is why you get skýrar, not a weak form.

It is in the nominative plural.

This is the normal case for the subject of a sentence. Since flokkunarleiðbeiningarnar is the subject, it appears in the nominative, and the adjective skýrar also matches that nominative plural form.

So structurally, the sentence is:

• Flokkunarleiðbeiningarnar = subject, nominative plural
• eru = verb
• skýrar = predicate adjective agreeing with the subject

No, the singular exists too.

• singular: leiðbeining
• plural: leiðbeiningar

In this sentence, the plural is used. If you wanted the singular definite version, it would be:

• flokkunarleiðbeiningin er skýr = the classification guideline is clear

Notice how everything changes to singular there:

• -in instead of -arnar
• er instead of eru
• skýr instead of skýrar

Yes. This is the basic and most neutral order:

• subject + verb + complement

So:

• Flokkunarleiðbeiningarnar = subject
• eru = verb
• skýrar = complement

This is the most straightforward way to say it.

You would put the verb first:

• Eru flokkunarleiðbeiningarnar skýrar? = Are the classification guidelines clear?

That verb-first pattern is very common in Icelandic yes/no questions.

The main dictionary forms are:

• flokkunarleiðbeining = classification guideline
• vera = to be
• skýr = clear

It is also useful to recognize the simpler noun inside the compound:

• leiðbeining = guideline, instruction

So if you are trying to look the sentence up, it helps to strip off endings and identify the base forms.