Hann er óþolinmóður svo lengi sem svarið kemur ekki, en hún bíður rólega.

Óþolinmóður means impatient.

It is built from:

• ó- = a negative prefix, like un- or im- in English
• þolinmóður = patient

So the whole word literally means something like not patient.

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

Here the adjective describes hann = he, which is:

• masculine
• singular
• nominative

So the correct form is the masculine singular nominative form: óþolinmóður.

If the subject were different, the adjective would change:

• hann er óþolinmóður = he is impatient
• hún er óþolinmóð = she is impatient
• þau eru óþolinmóð = they are impatient

Svo lengi sem is a set expression meaning as long as.

In this sentence, it introduces a time-related subordinate clause:

• svo lengi sem svarið kemur ekki = as long as the answer does not come

Depending on context, it can feel like:

• as long as
• for as long as
• sometimes while

Here as long as is the most natural match.

Because svarið is the definite form of svar.

• svar = answer
• svarið = the answer

Icelandic often adds the definite article to the end of the noun instead of using a separate word like the.

So:

• svar = answer
• svarið = the answer

In this sentence, svarið is the subject of kemur.

Svarið is in the nominative singular.

That is because it is the subject of the verb kemur:

• svarið kemur ekki = the answer does not come / the answer does not arrive

The noun svar is neuter, and svarið is its nominative singular definite form.

In Icelandic, ekki usually comes after the finite verb.

So:

• svarið kemur ekki = the answer does not come

This is the normal placement of negation in a clause like this.

A useful pattern to remember is:

• subject + finite verb + ekki

For example:

• hann skilur ekki = he does not understand
• hún kemur ekki = she does not come

Yes. In Icelandic, koma can mean both come and arrive, depending on context.

So svarið kemur ekki can be understood as:

• the answer does not come
• the answer does not arrive

In English, arrive may sound more natural, but Icelandic often uses koma in situations where English might use arrive, turn up, or come in.

Because bíður is the correct 3rd person singular present form of the verb bíða = to wait.

The present tense forms include:

• ég bíð = I wait
• þú bíður = you wait
• hann/hún/það bíður = he/she/it waits

So with hún, the correct form is:

• hún bíður = she waits

Yes, bíða often takes a genitive object when you say what someone is waiting for.

For example:

• bíða svars = wait for an answer
• bíða hans = wait for him

But in your sentence, no object is stated explicitly:

• hún bíður rólega = she waits calmly

So the sentence focuses on how she waits, not what she is waiting for.

Because rólega is an adverb, while rólegur / róleg / rólegt are adjective forms.

Here the word describes how she waits, so Icelandic uses the adverb:

• hún bíður rólega = she waits calmly

Compare:

• hún er róleg = she is calm
  
  • here róleg is an adjective describing hún
• hún bíður rólega = she waits calmly
  
  • here rólega is an adverb describing bíður

It has three parts:

1. Hann er óþolinmóður
   = main clause

2. svo lengi sem svarið kemur ekki
   = subordinate clause introduced by svo lengi sem

3. en hún bíður rólega
   = another main clause, linked by en = but

So the structure is:

• main clause
• subordinate time clause
• contrasting main clause

That is why the sentence feels like:

• He is impatient as long as the answer does not come, but she waits calmly.

En means but.

It connects the first part of the sentence with a contrasting second part:

• Hann er óþolinmóður ... = He is impatient ...
• en hún bíður rólega = but she waits calmly

So en signals a contrast between the two people:

• he is impatient
• she waits calmly

These are two very important Icelandic letters:

• þ is pronounced like th in thin
• ð is usually pronounced like th in this

From this sentence:

• óþolinmóður has þ
• svarið and bíður have ð

So a rough guide is:

• þ = unvoiced th
• ð = voiced th

That is not the whole story of Icelandic pronunciation, but it is a very good starting point.