Klippingin var styttri en ég hélt.

Klipping is a feminine noun that can mean a haircut, a cutting/clipping, or a clip, depending on context. In this sentence, it most naturally means the haircut or the cut.

The ending -in is the suffixed definite article in Icelandic, so:

• klipping = a haircut / haircut
• klippingin = the haircut

Icelandic usually adds the to the end of the noun instead of using a separate word like English does.

Var is the past tense of vera (to be).

• er = is
• var = was

So:

• Klippingin er styttri = The haircut is shorter
• Klippingin var styttri = The haircut was shorter

This sentence is talking about a past situation, so var is the correct form.

Styttri is the comparative form of stuttur (short).

Like English:

• short
• shorter

In Icelandic:

• stuttur = short
• styttri = shorter

So Klippingin var styttri means The haircut was shorter.

This comparative form is used before en (than), just like in English:

• styttri en... = shorter than...

That is a very common question. In the comparative, Icelandic adjectives often use forms that do not show gender as clearly as the positive form does.

For the adjective stuttur:

• positive: stuttur (masculine), stutt (neuter), stutt/stutt? feminine forms differ by case and inflection
• comparative: styttri

In this sentence, styttri is the normal comparative form used with klippingin.

So the key point is:
you do not expect a separate obvious feminine form here in the way you might in the positive degree. The comparative adjective form is simply styttri.

En means than in comparisons.

So:

• styttri en ég hélt = shorter than I thought

Be careful, because en can also mean but in other sentences. Icelandic uses the same word for both meanings, and the context tells you which one it is.

Here it is clearly the comparison word than.

Hélt is the past tense of halda, which very often means to think, to suppose, or to believe in expressions like this.

So:

• ég held = I think
• ég hélt = I thought

In this sentence:

• en ég hélt = than I thought

Even though halda can also mean hold, in many common expressions it means think / believe / suppose.

Icelandic often leaves that kind of extra clause material unstated when it is understood from context, just like English often does.

English says:

• The haircut was shorter than I thought.

We do not have to say:

• The haircut was shorter than I thought it was.

Icelandic works similarly:

• Klippingin var styttri en ég hélt.

The rest is understood. The speaker means something like:

• The haircut was shorter than I thought it would be / than I thought it was going to be.

So the sentence is complete and natural as it stands.

Yes. After a comparative adjective like styttri (shorter), Icelandic commonly uses en plus a clause:

• eldri en ég hélt = older than I thought
• betri en ég bjóst við = better than I expected
• styttri en ég hélt = shorter than I thought

So the structure is:

• [noun] + var + [comparative adjective] + en + [clause]

This is a very useful pattern to learn.

It is in the nominative singular.

That is because it is the subject of the sentence:

• Klippingin = the thing being described
• var styttri = was shorter

So the basic structure is:

• Subject: Klippingin
• Verb: var
• Complement: styttri en ég hélt

It depends on context.

Possible meanings of klipping include things like:

• haircut
• clipping
• cut

In everyday speech, if people are talking about hair, then Klippingin var styttri en ég hélt would most naturally mean:

• The haircut was shorter than I thought.

In another context, it could mean something like:

• The cut/clipping was shorter than I thought.

So the grammar stays the same, but the exact noun meaning depends on the situation.

A close breakdown would be:

• Klipping-in = haircut-the
• var = was
• styttri = shorter
• en = than
• ég = I
• hélt = thought

So very literally:

• The haircut was shorter than I thought.

This is actually quite close to English in structure, which makes it a nice sentence for learners.

The accent in é shows that it is a different vowel sound from plain e. In Icelandic, accented vowels are considered distinct letters, not just stressed versions of the same vowel.

So:

• e and é are different vowels
• hélt is pronounced with é, not plain e

The accent matters for both spelling and pronunciation, and often you simply need to learn the correct form as part of the word.

Yes, absolutely. This is a very common Icelandic pattern.

Examples:

• Myndin var betri en ég hélt.
  The film was better than I thought.

• Herbergið var stærra en ég hélt.
  The room was bigger than I thought.

• Bókin var erfiðari en ég hélt.
  The book was more difficult than I thought.

So once you know the pattern:

• [something] var [comparative] en ég hélt

you can use it very widely.