Poslije posla ću se opustiti u vrtu.

A literal breakdown is:

• Poslije = after
• posla = work / the job (in a special form: genitive)
• ću = I will
• se = a reflexive particle, often used in verbs like opustiti se = to relax
• opustiti = relax, unwind
• u = in
• vrtu = garden (in a special form: locative)

So the sentence structure is roughly:

After work, I will relax in the garden.

Because poslije (after) requires the genitive case.

The basic form is:

• posao = work, job

But after poslije, it changes to:

• posla = of work / after work

So:

• poslije posla = after work

This is very common in Croatian: certain prepositions force the noun into a particular case.

Because u can take two different cases depending on meaning:

• u + accusative = movement into somewhere
• u + locative = being in somewhere

Here, the sentence describes location, not motion:

• u vrtu = in the garden

Compare:

• Idem u vrt. = I’m going into the garden.
• Ja sam u vrtu. = I’m in the garden.

In your sentence, the person will be relaxing in the garden, so locative is used: vrtu.

Croatian future tense here is formed with:

• the auxiliary ću (I will)
• the infinitive opustiti (to relax)

So:

• ću opustiti would literally be I will relax

But because Croatian clitics have special placement rules, it becomes:

• ću se opustiti

The full idea is:

• Ja ću se opustiti = I will relax

In this sentence, ja is omitted because Croatian often drops subject pronouns when they are already clear from the verb.

Because the natural Croatian verb for to relax is usually opustiti se.

This se is a reflexive particle. In many cases, English uses a simple verb where Croatian uses a reflexive form.

So:

• opustiti se = to relax, to unwind

Without se, opustiti usually means something more like:

• to loosen
• to relax something
• to release

For example:

• Opustio je mišiće. = He relaxed his muscles.

But:

• Opustio se. = He relaxed.

This is about aspect, which is very important in Croatian.

• opustiti se = perfective
• opuštati se = imperfective

In this sentence, opustiti se is used because it refers to a single future action viewed as a whole:

• Poslije posla ću se opustiti. = After work I’ll relax / I’ll unwind.

If you used opuštati se, it would sound more like an ongoing, repeated, or habitual action, depending on context.

Very roughly:

• opustiti se = to relax (once / successfully / as a complete action)
• opuštati se = to be relaxing / to relax regularly / to spend time relaxing

Because ću is a clitic in Croatian. Clitics are short unstressed words that usually go in second position in the sentence or clause.

So in:

• Poslije posla ću se opustiti u vrtu.

the first unit is Poslije posla, and then the clitic ću comes after it.

This is normal Croatian word order.

You can also say:

• Ja ću se opustiti u vrtu poslije posla.
• Opustit ću se u vrtu poslije posla.

All are possible, but the clitic placement has to follow Croatian rules.

Because Croatian often omits subject pronouns when the meaning is already clear from the verb.

Here, ću already tells you it is first person singular:

• ću = I will

So ja is unnecessary unless you want emphasis or contrast.

Compare:

• Ću se opustiti. = not correct by itself, because clitics need proper placement
• Ja ću se opustiti. = I will relax.
• Poslije posla ću se opustiti. = After work, I will relax.

If you say ja, it can sound more emphatic, like I will relax.

Yes. Both are natural and common.

• Poslije posla = after work
• Nakon posla = after work

Both take the genitive case, so you still say posla, not posao.

The difference is mostly stylistic or regional in some contexts, not a big difference in meaning.

Yes. Croatian word order is more flexible than English, although not completely free. Different orders can sound more natural depending on what you want to emphasize.

For example:

• Poslije posla ću se opustiti u vrtu.
  Neutral; after work is placed first.

• U vrtu ću se opustiti poslije posla.
  More emphasis on in the garden.

• Opustit ću se u vrtu poslije posla.
  Also very natural.

The meaning stays basically the same, but the focus shifts a little.

Both are correct, but the form changes slightly when the infinitive comes before the auxiliary.

Compare:

• Ću se opustiti → not correct at the beginning by itself because of clitic placement
• Ja ću se opustiti
• Opustit ću se

When the infinitive comes before ću, the final -i of the infinitive is usually dropped in writing:

• opustiti + ću → opustit ću

So these are equivalent:

• Ja ću se opustiti.
• Opustit ću se.

Both mean I will relax.

Usually in the garden.

Croatian u most often corresponds to in when talking about location inside or within a place:

• u kući = in the house
• u sobi = in the room
• u vrtu = in the garden

In some situations, English might use at, but for vrt, in the garden is the most natural translation.

vrtu is locative singular.

The basic dictionary form is:

• vrt = garden

After u meaning location, it becomes:

• u vrtu = in the garden

So:

• nominative: vrt
• locative: vrtu

This is a common masculine noun pattern in Croatian.