Mér finnst óraunhæft að vakna klukkan fimm á hverjum virkum degi.

Because finnast in this kind of sentence takes the person experiencing the opinion in the dative, not the nominative.

• ég = I (nominative)
• mér = to me / me (dative)

So mér finnst literally means something like to me, it seems / feels / is found.

This is a very common Icelandic pattern:

• Mér finnst þetta gott. = I think this is good.
• Mér finnst hann skemmtilegur. = I think he is fun.

So even though English uses I, Icelandic often uses mér with finnast.

In everyday Icelandic, mér finnst often means:

• I think
• I feel
• I find
• it seems to me

In this sentence, the closest English idea is I find it unrealistic.

It is often used for personal judgments or impressions, so it sounds more subjective and natural than a more formal verb like halda in many contexts.

Icelandic does not always need an expressed dummy subject like English it.

In English:

• I find it unrealistic to wake up at five...

In Icelandic:

• Mér finnst óraunhæft að vakna...

The idea being judged is the infinitive phrase að vakna klukkan fimm á hverjum virkum degi. Icelandic often lets that clause carry the meaning without inserting a separate word for it.

So the English it is not translated directly here.

Because it is describing an idea/action rather than a specific masculine, feminine, or plural noun.

The adjective comes from:

• óraunhæfur = unrealistic

Its neuter singular form is:

• óraunhæft

Icelandic very often uses the neuter singular as a default form when the thing being described is:

• an infinitive phrase
• a clause
• a general situation

Here, what is unrealistic is the whole action:

• að vakna klukkan fimm á hverjum virkum degi

So óraunhæft is exactly the form you would expect.

að vakna means to wake up.

• vakna = wake up
• að = the infinitive marker, like English to

So:

• að vakna = to wake up

After adjectives like óraunhæft, Icelandic often uses an infinitive phrase to say what is unrealistic, difficult, nice, important, and so on.

Compare:

• Það er gott að hvíla sig. = It is good to rest.
• Það er erfitt að læra þetta. = It is difficult to learn this.

Because vakna and vekja are different verbs.

• vakna = to wake up, become awake
• vekja = to wake someone up

So:

• Ég vakna klukkan fimm. = I wake up at five.
• Ég vek barnið klukkan fimm. = I wake the child up at five.

In your sentence, the subject is the person who wakes up, not someone waking another person, so vakna is correct.

klukkan fimm means at five o’clock.

This is a standard Icelandic time expression:

• klukkan eitt = at one o’clock
• klukkan fimm = at five o’clock
• klukkan átta = at eight o’clock

English needs the preposition at, but Icelandic often does not in this pattern. The expression itself already functions adverbially.

So:

• að vakna klukkan fimm = to wake up at five

This phrase means on every working day or more naturally every weekday.

It breaks down like this:

• á = on
• hverjum = each / every (dative singular)
• virkum = working / weekday-related (dative singular)
• degi = day (dative singular)

So the whole phrase literally means on each working day.

In English, we usually say every weekday.

Because the preposition á often takes the dative when it refers to location or a repeated time setting like this.

Here it is part of a time expression:

• á hverjum virkum degi = on every weekday

Since á governs the dative here, all the words in that noun phrase match in the dative singular:

• hver → hverjum
• virkur → virkum
• dagur → degi

This agreement is completely normal in Icelandic noun phrases.

Literally, virkur can mean active or working/operative, depending on context.

But in the phrase virkur dagur, it usually means a working day, that is, a weekday rather than a weekend day.

So in this sentence:

• á hverjum virkum degi = every weekday

That is the natural meaning here, not every active day.

Yes. Icelandic word order is flexible, though not random.

The original sentence is:

• Mér finnst óraunhæft að vakna klukkan fimm á hverjum virkum degi.

You could also say:

• Að vakna klukkan fimm á hverjum virkum degi finnst mér óraunhæft.

This version puts more emphasis on the action itself.

A useful rule to remember is that in main clauses, Icelandic normally follows the verb-second pattern: whatever comes first, the finite verb usually comes second.

So in the original:

• first element: Mér
• second element: finnst

That is why the order looks the way it does.