Endirinn var óvæntur.

Because Icelandic very often puts the definite article onto the end of the noun instead of using a separate word.

So:

• endir = ending
• endirinn = the ending

The ending -inn here is the masculine singular definite article.

The dictionary form is endir.

In this sentence, endirinn is the definite singular form: endir + -inn.

So if you look the word up, you would normally look for endir, not endirinn.

Because the noun itself is endir. When the definite article is added, Icelandic keeps that noun form and gives endirinn.

A helpful comparison is:

• læknir → læknirinn
• endir → endirinn

So you should think of it as a whole inflected form of endir, not as a shortened stem plus -inn.

Endirinn is in the nominative singular.

That is because it is the subject of the sentence: the ending is the thing being described as unexpected.

It is also masculine, because endir is a masculine noun.

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

Here, endirinn is:

• masculine
• singular
• nominative

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

• óvæntur

If the noun were different, the adjective form would change too.

Because after the verb vera (to be), predicate adjectives usually match the subject.

In Endirinn var óvæntur, the structure is:

• Endirinn = subject
• var = was
• óvæntur = predicate adjective

Since the subject is nominative masculine singular, the adjective matches it.

Because var is the past tense of vera (to be).

So:

• er = is
• var = was

That means the sentence is talking about the ending as unexpected in the past.

Yes. Var is a form of vera, and vera is highly irregular.

That means its forms do not all look similar in the way regular verbs do. This is normal for very common verbs in many languages, including English:

• be
• am
• is
• was

Icelandic works similarly:

• vera = to be
• er = is
• var = was

Yes, this is a very normal, neutral word order:

• Endirinn = subject
• var = verb
• óvæntur = complement

So Endirinn var óvæntur is a straightforward way to say it.

Icelandic does allow other word orders for emphasis, though. For example, Óvæntur var endirinn is possible, but it sounds more marked or literary.

You would usually say:

• óvænti endirinn = the unexpected ending

This is different from Endirinn var óvæntur because now the adjective is placed before the noun, not after to be.

That matters in Icelandic:

• Endirinn var óvæntur = predicative adjective
• óvænti endirinn = attributive adjective

In the attributive version, the adjective takes a weak form because the noun is definite.

Yes, very often.

The prefix ó- commonly gives a negative meaning, much like English un-, in-, or non-.

So in a word like óvæntur, it helps create the idea of something not expected or unexpected.

This is a useful pattern to notice in Icelandic vocabulary.

A rough English-friendly guide is:

• ó sounds roughly like o in go
• æ sounds roughly like eye
• r is pronounced more clearly than in most English accents

So óvæntur is approximately OH-vine-tur as a rough guide.

That is only approximate, but the most important thing for learners is usually noticing:

• ó = long oh
• æ = eye

A rough guide is something like EN-di-rin.

A few useful points:

• stress is on the first syllable
• the r should be pronounced
• the final -inn is a real ending, so do not swallow it completely

So the rhythm is roughly:

• EN-di-rinn

Not perfect English-style spelling, but good enough as a starting point.