Pošto put traje samo jedan dan, neću spakirati previše odjeće.

Here pošto means since / because.

So:

• Pošto put traje samo jedan dan... = Since the trip lasts only one day...

It is similar to jer (because), but there is a small difference in how it is typically used:

• jer directly introduces a reason
• pošto often sounds a bit like since / given that

So both are possible in many contexts:

• Jer put traje samo jedan dan...
• Pošto put traje samo jedan dan...

In this sentence, pošto sounds very natural.

One important note: pošto can also mean after, depending on context, but not here.

Because the sentence begins with a subordinate clause.

Croatian often uses a comma before or after dependent clauses, just like English does in sentences such as:

• Since the trip lasts only one day, I won’t pack too many clothes.

So the structure is:

• Pošto put traje samo jedan dan, = subordinate clause
• neću spakirati previše odjeće. = main clause

The comma is standard here.

In this sentence, put means trip / journey.

Croatian put can mean:

• road / way / path in some contexts
• trip / journey in others

Here, because it is something that traje samo jedan dan (lasts only one day), it clearly means trip / journey.

Examples:

• Dug je put do Zagreba. = It’s a long הדרך / trip to Zagreb.
• Na put idem sutra. = I’m going on a trip tomorrow.

So in this sentence, think of put as trip.

Because trajati (to last) is a normal lexical verb, not a form with to be.

So:

• put traje = the trip lasts

You do not add je here.

Compare:

• Put je dug. = The trip is long.
  Here je is needed because dug is an adjective.
• Put traje jedan dan. = The trip lasts one day.
  Here traje is the main verb.

So traje already carries the meaning of the verb.

Because with trajati to express duration, Croatian commonly uses the accusative.

So:

• trajati jedan dan = to last one day
• trajati dva dana = to last two days
• trajati tjedan dana = to last a week

Here:

• jedan = accusative masculine singular
• dan = accusative singular, which looks the same as nominative for this noun

That is why you see jedan dan.

Because Croatian forms the future tense with:

• a form of htjeti (to want, used as a future auxiliary)
• plus the infinitive

Here:

• ću = future auxiliary for I
• neću = negative form, I will not / I won’t
• spakirati = infinitive, to pack

So:

• spakirat ću = I will pack
• neću spakirati = I will not pack

In affirmative sentences, you often see the auxiliary after the infinitive stem in writing:

• spakirat ću or spakirati ću is something learners may notice, but standard usage strongly prefers spakirat ću only with the shortened infinitive in actual orthography?
  More importantly for learners, the normal full form you should remember is:
• Ja ću spakirati... = I will pack...

But in the negative, the auxiliary stays together as neću, and the infinitive remains separate:

• neću spakirati

That pattern is very important.

Because in standard Croatian, the negative future form is written as one word:

• neću
• nećeš
• neće
• nećemo
• nećete
• neće

So:

• Neću doći. = I won’t come.
• Neće spavati. = He/She won’t sleep.

Writing ne ću is nonstandard.

Yes, and the choice changes the nuance.

• spakirati = to pack up / to finish packing → perfective
• pakirati = to be packing / to pack → imperfective

In this sentence, spakirati is natural because the speaker is talking about a completed action in the future:

• I won’t pack too many clothes.

The focus is on the result: what will or will not end up packed.

If you used pakirati, it would sound more like the process or habit of packing, and it would be less natural here.

So neću spakirati is the best choice.

Previše means too much / too many.

Here it works as an indeclinable quantity word, so it does not change form.

Examples:

• previše vode = too much water
• previše ljudi = too many people
• previše odjeće = too many clothes / too much clothing

So in this sentence:

• previše odjeće = literally too much of clothing
• natural English: too many clothes

Because quantity expressions like previše are followed by the genitive.

So:

• previše odjeće
• puno vremena
• malo novca
• dosta ljudi

Here odjeće is the genitive form of odjeća (clothing / clothes).

This is a very common Croatian pattern:

• quantity word + genitive noun

So even though English says too many clothes, Croatian uses a structure closer to too much clothing.

Grammatically, odjeća is singular, but it often refers to clothing / clothes as a collective idea.

So:

• odjeća = clothing / clothes
• genitive singular: odjeće

That is why:

• previše odjeće literally looks singular
• but in English it is often best translated as too many clothes

Croatian often uses a singular collective noun where English prefers a plural noun.

Yes, absolutely.

Both are possible, but they are slightly different:

• spakirati odjeću = to pack clothes
• ponijeti odjeću = to take/bring clothes along

So:

• Neću spakirati previše odjeće.
  Focus: what I will pack into my bag/suitcase.
• Neću ponijeti previše odjeće.
  Focus: what I will take with me on the trip.

In many travel contexts, both are natural.

Yes.

Croatian usually drops subject pronouns when they are not needed, because the verb form already shows the person.

Here:

• neću already means I will not

So:

• Neću spakirati previše odjeće. = I won’t pack too many clothes.

You could add ja for emphasis:

• Ja neću spakirati previše odjeće.

But without emphasis, leaving it out is more natural.

The sentence has a very normal Croatian word order:

• Pošto put traje samo jedan dan, neću spakirati previše odjeće.

Literally:

• Since trip lasts only one day, I-won’t pack too-much clothing.

Croatian word order is fairly flexible, but not completely free. You could change it for emphasis, for example:

• Pošto put traje samo jedan dan, previše odjeće neću spakirati.

This puts more emphasis on previše odjeće.

But the original version is the most neutral and natural for a learner to use.