Learn Hardcore Icelandic: Við förum í útivist á mánudögum til að verða hressari eftir vinnu. - We do outdoor activities on Mondays to become more energetic after work.

Við – we (nominative plural pronoun)
förum – go (1st person plural, present tense of fara)
í – in/into (preposition, governs accusative here)
útivist – literally out-being / being outdoors → outdoor activity / recreation (accusative singular)
á mánudögum – on Mondays (preposition á
- dative plural mánudögum = “on Mondays (regularly)”)
til að – in order to (purpose clause marker + infinitive marker)
verða – to become (infinitive)
hressari – more refreshed / more lively / more energized (comparative of hress)
eftir vinnu – after work (preposition eftir
- accusative singular vinnu)

Natural English: We go do outdoor activities on Mondays to feel more refreshed after work.

Why is it förum and not faram or something similar?

Förum is the correct 1st person plural present form of the verb fara (to go). The verb is irregular and has a vowel change (umlaut):

ég fer – I go
þú ferð – you (sg.) go
hann / hún / það fer – he / she / it goes
við förum – we go
þið farið – you (pl.) go
þeir / þær / þau fara – they go

Notice:

The infinitive is fara.
In förum, a changes to ö and the ending -um marks 1st person plural present for many verbs.

So við förum is the standard “we go” in the present tense.

What exactly does útivist mean? Is it just “outdoors”?

Útivist is a noun and is broader than simply “outdoors.” Literally it’s “out-being” (being outside), but in modern usage it means:

outdoor activities, outdoor recreation, spending time outside for leisure or health.

Depending on context, it can cover:

going for a walk or hike
camping
skiing, jogging, general exercise outside
“getting some fresh air”

The phrase fara í útivist is very idiomatic and means something like:

to go do some outdoor activities
to go outside for recreation / exercise

Why do we say fara í útivist? Why í + noun?

Icelandic often uses fara í + [accusative noun] to mean “go and do [activity]”. For example:

fara í sund – go (to) swimming
fara í bíó – go to the cinema
fara í göngutúr – go for a walk
fara í útivist – go do outdoor activities

The preposition í with the accusative frequently expresses going into or engaging in an activity. So í útivist is not “in outdoor” literally; it’s “into outdoor recreation” → “to do outdoor activities.”

Why is it á mánudögum and not á mánudaga or á mánudag?

Á mánudögum is in the dative plural and is the standard way to say “on Mondays” (habitually, every Monday).

mánudagur – Monday (nominative singular)
á mánudaginn (accusative singular with article) – on Monday (a specific Monday, often “this/next Monday”)
á mánudögum (dative plural) – on Mondays (every Monday, regularly)

So:

Við förum í útivist á mánudögum. – We go do outdoor activities on Mondays (as a regular routine).
Við förum í útivist á mánudaginn. – We will go do outdoor activities on Monday (that specific Monday).

The dative plural with á is the pattern for regular repeated days:
á mánudögum, á þriðjudögum, á föstudögum, etc.

Why is there til að verða instead of just að verða?

The sequence til að + infinitive is a very common way in Icelandic to express purpose: “in order to …”

til – to / for (here: for the purpose of)
að – infinitive marker
verða – to become

So til að verða hressari literally means “in order to become more refreshed.”

If you said only að verða hressari eftir vinnu, it would just look like a bare infinitive phrase, not clearly marked as expressing purpose. Til að makes it explicit that this is why you go for outdoor activities.

Compare:

Ég lærði mikið til að standast prófið. – I studied a lot (in order) to pass the exam.
Hann fór snemma til að ná strætó. – He left early (in order) to catch the bus.

What does hressari mean, and how is it formed?

Hressari is the comparative form of the adjective hress.

hress – fresh, lively, in good spirits, energized
hressari – fresher / more lively / more energized

Formation:

Many regular adjectives form the comparative with -ari:
- skemmtilegur → skemmtilegri (more fun)
- sterkur → sterkari (stronger)
- hress → hressari (more refreshed / more lively)

In context, verða hressari means “to become more refreshed / to feel more energized.”

Why is it eftir vinnu and not eftir vinnuna?

Both are possible, but they are slightly different in nuance.

eftir vinnu – literally after work (work in general, the working period). This is the most idiomatic way to mean “after work” as a routine, unspecific thing.
eftir vinnuna – literally after the work (more specific: after that particular work / shift / job).

In everyday speech about daily routine, eftir vinnu is the normal phrase for:

“after work (when I have finished my workday)”

Grammatically:

vinna – work (noun, feminine)
vinnu – accusative singular
The preposition eftir here governs the accusative to express “after [something in time].”

Why is vinna in the accusative after eftir?

The preposition eftir can govern either dative or accusative, depending on meaning:

eftir + dative often has meanings like “after, according to, by (someone)” in a more static sense (following, according to).
eftir + accusative is used for time: after something (in time).

In the phrase eftir vinnu, we’re talking about time (“after work (time)”), so accusative is used:

eftir vinnu – after work (when work is over)
eftir skólann – after school
eftir leikinn – after the game

So vinnu is accusative singular feminine of vinna.

Could the sentence word order be changed, for example Á mánudögum förum við í útivist…?

Yes, Icelandic word order is relatively flexible, especially with adverbials. You can move á mánudögum to the front for emphasis or style:

Við förum í útivist á mánudögum til að verða hressari eftir vinnu.
Neutral order; “on Mondays” is in the middle.
Á mánudögum förum við í útivist til að verða hressari eftir vinnu.
Puts emphasis on “On Mondays”, like: “On Mondays, we go do outdoor activities…”

Both are grammatical and natural. Just keep the finite verb (förum) in second position in the clause, which these versions do:

Við (1st) – förum (2nd) – í útivist …
Á mánudögum (1st) – förum (2nd) – við …

Could I say Við förum út á mánudögum instead of í útivist? Does it mean the same?

You can say Við förum út á mánudögum, but it is less specific:

Við förum út á mánudögum. – We go outside on Mondays.
Við förum í útivist á mánudögum. – We do outdoor activities on Mondays.

fara út just means “go outside” (maybe briefly, without implying exercise or particular activity).

fara í útivist strongly suggests conscious outdoor recreation/activities, which matches the idea of going out to become more refreshed. So í útivist is the better choice if you mean organized or intentional outdoor activity for health/fun.

Is við always necessary in a sentence like this, or can it be dropped like in some other languages?

In Icelandic, subject pronouns are generally not dropped the way they are in some “pro-drop” languages (like Spanish, Italian).

So:

Við förum í útivist á mánudögum… – is the standard, correct form.
Förum í útivist á mánudögum… – without við sounds incomplete or imperative (“Let’s go do outdoor activities on Mondays”), not a simple statement.

In commands, you might drop the subject:

Förum í útivist! – Let’s go do outdoor activities!

But for a normal declarative sentence describing a habit, við needs to be there.

How would you pronounce the main words in this sentence?

Approximate pronunciations (using a rough English-friendly system):

Við – like vith (with a soft th as in this; short i)
förum – roughly fur-um (ö like in British bird but shorter; r rolled)
í – like ee (long)
útivist – OO-tee-vist (ú is long oo; both ts are clear)
á – like ow in cow but usually longer
mánudögum – MOW-nu-thoe-gum
- má – like mow (as in to mow the lawn)
- nu – nu with short u like in book
- dögum – thœ-gum (ð is th in this, ö as above, final um is short and weak)
til að – til ath (ð is usually very soft, almost disappearing in fast speech)
verða – VER-tha (ð like th in this)
hressari – HRESS-ar-i (hr is breathy, r rolled, stress on first syllable)
eftir – EF-tir (short e, clear f and t)
vinnu – VIN-nu (short i like bit, double nn pronounced long, u as in book)

This is only approximate, but it can help with getting in the right ballpark before listening to native audio.