Ég greiði hárið hægt, þar sem það er enn blautt eftir sturtu.

Greiði is the 1st person singular present tense of greiða.

In Icelandic, the simple present often does jobs that English splits between:

• I comb
• I am combing

So Ég greiði hárið hægt can be a perfectly normal way to say this.

If you want to stress that the action is happening right now, Icelandic can also use vera að + infinitive:

• Ég er að greiða hárið = I am combing my hair

The version in your sentence is more neutral and straightforward.

Yes — greiða has more than one meaning.

Common uses include:

• greiða hárið = comb / brush the hair
• greiða reikning = pay a bill
• greiða skuld = pay a debt

So the meaning depends a lot on the object. With hárið, the meaning is clearly comb/brush.

Hárið is hár + the suffixed definite article, so literally it means the hair.

Icelandic often uses the definite form with body parts where English would usually use a possessive:

• Ég þvæ hendurnar = I wash my hands
• Hann lokaði augunum = He closed his eyes
• Ég greiði hárið = I comb my hair

So even though Icelandic says something closer to the hair, the natural English meaning is usually my hair here.

Because Icelandic usually does not need a possessive with body parts when the owner is obvious from the sentence.

Since the subject is ég, it is naturally understood that hárið is the speaker’s hair.

Using hár mitt is possible, but it would usually sound more emphatic or contrastive, as if you were stressing my hair rather than someone else’s.

It is the direct object of greiði, so it is in the case that this verb takes for its object.

With hár, the singular nominative and accusative forms look the same, and the same is true with the definite form hárið. So even though case is still there grammatically, you do not see a different ending here.

Because hægt is being used as an adverb.

The adjective is:

• hægur = slow

Its neuter singular form is:

• hægt

Very often in Icelandic, the neuter singular form of an adjective is also used adverbially:

• hann talar hægt = he speaks slowly
• hún keyrir hratt = she drives fast

So greiði hárið hægt means comb the hair slowly.

Here þar sem means since, because, or as.

Even though þar often has a literal meaning like there, the whole expression þar sem is a common conjunction introducing a reason:

• Ég fer ekki út, þar sem það rignir. = I’m not going out, since it’s raining.

So in your sentence, it gives the reason for combing the hair slowly.

Because þar sem introduces a subordinate clause.

In Icelandic, main clauses often follow the verb-second pattern, but subordinate clauses usually do not. So after þar sem, the normal order is:

• conjunction + subject + verb

That is why you get:

• þar sem það er enn blautt

and not a main-clause style order with the verb moved forward.

Það refers back to hárið.

Since hár is a neuter singular noun, words agreeing with it also appear in the neuter singular:

• það = neuter singular pronoun
• blautt = neuter singular form of blautur = wet

So:

• hárið → neuter singular
• therefore það er enn blautt

If the noun were feminine or masculine, the forms would change accordingly.

Enn means still here.

So:

• enn blautt = still wet

It shows that the hair remains wet at this point. Its placement before the adjective is normal.

Because Icelandic often leaves out the article in expressions like this when the meaning is generic or situationally obvious.

So eftir sturtu means:

• after a shower
• after showering

It does not need to mean one very specific shower in the same way English often uses a.

Also, sturtu is the expected oblique form after the preposition eftir in this expression.

Yes. It is normal to put a comma before a subordinate clause like this, especially when it gives extra explanation or a reason.

So the comma in:

• Ég greiði hárið hægt, þar sem það er enn blautt eftir sturtu.

is completely natural.