Tjuven gick förbi huset.

Because tjuven is the definite form of tjuv.

• tjuv = a thief
• tjuven = the thief

In Swedish, the definite article is usually added as an ending rather than written as a separate word before the noun.

So:

• en tjuv = a thief
• tjuven = the thief

This is very common in Swedish.

For the same reason: huset is the definite form of hus.

• ett hus = a house
• huset = the house

Swedish often puts the definite article at the end of the noun:

• common gender nouns often take -en
• neuter nouns often take -et

Here:

• hus is a neuter noun (ett hus)
• so the house becomes huset

Because Swedish usually expresses the by attaching it to the noun as a suffix.

Compare:

• English: the thief

• Swedish: tjuven

• English: the house
• Swedish: huset

This is one of the biggest structural differences from English.
Instead of a separate article before the noun, Swedish often uses an ending:

• -en / -n
• -et / -t

There are also cases where Swedish uses a separate word like den, det, or de, but in a simple sentence like this, the ending is enough.

Gick is the past tense of gå, which means to go / to walk.

So:

• gå = to go, to walk
• går = goes / is going
• gick = went
• gått = gone / walked

This verb is irregular, so you cannot predict gick from the infinitive gå just by adding a regular ending.

Examples:

• Jag går hem. = I go home / I am walking home.
• Jag gick hem. = I went home.

It can often cover both ideas, depending on context.

Gå literally relates to walking, but in many situations Swedish uses it where English would simply say go.

So gick may suggest movement on foot, but in many sentences the most natural English translation is just went.

In Tjuven gick förbi huset, the idea is that the thief moved past the house, very likely on foot. English might translate that as:

• The thief walked past the house or
• The thief went past the house

Both can work depending on context.

Förbi means past or by, in the sense of moving beyond something.

In this sentence, gick förbi huset means went/walked past the house.

You can think of förbi as expressing movement past a point or object.

Examples:

• Hon gick förbi skolan. = She walked past the school.
• Bilen körde förbi oss. = The car drove past us.

It is a very common word with verbs of movement.

It is often taught as an adverb, but in sentences like this it behaves very much like a word introducing what is being passed, so from a learner’s point of view it is fine to think of gå förbi något as a common pattern meaning go past something.

What matters most is the usage:

• gå förbi huset = go past the house
• köra förbi bilen = drive past the car
• springa förbi honom = run past him

So even if grammar books may classify it carefully in different ways, the practical learner takeaway is:

verb of movement + förbi + noun
= movement past something

Yes, but it would mean something different.

• Tjuven gick förbi huset = the thief went past the house
• Tjuven gick förbi ett hus = the thief went past a house

So the difference is definiteness:

• huset = the specific house
• ett hus = any house / an unspecified house

Yes. This is very normal Swedish word order for a main clause:

Subject + verb + rest

So:

• Tjuven = subject
• gick = verb
• förbi huset = the rest of the sentence

This is the most basic and natural order in Swedish.

Yes. Swedish often allows another element to come first, but then the verb still has to stay in second position.

For example:

• Förbi huset gick tjuven.

This is possible, but it sounds more marked or literary, because förbi huset is being emphasized.

That is because Swedish follows the V2 rule in main clauses: the finite verb must come in the second position.

So:

• Tjuven gick förbi huset.
• Förbi huset gick tjuven.

Both are grammatical, but the first is the neutral everyday version.

Because förbi and för mean very different things.

• förbi = past, by
• för = for, because of, in front of in some fixed expressions, and other meanings depending on context

So gick förbi huset means the thief moved past the house.

If you replaced förbi with för, the sentence would no longer mean the same thing and would usually sound wrong in this context.

Yes. Passerade is the past tense of passera, and it means passed.

So:

• Tjuven gick förbi huset.
• Tjuven passerade huset.

Both are correct, but they feel slightly different:

• gick förbi emphasizes the action of going/walking past
• passerade is a little more neutral or formal, and does not by itself focus as much on the manner of movement

If you specifically want the idea of walking, gick förbi is very natural.

A rough learner-friendly guide:

• tjuven ≈ SHOO-ven
  The first sound is the Swedish tj sound, which does not exist exactly in English. A rough sh is an acceptable beginner approximation.

• gick ≈ yik
  The g sounds like English y before this vowel.

• förbi ≈ fur-BEE
  The ö is not exactly like English u, but fur is a rough approximation.

• huset ≈ HOO-set
  The Swedish u is not exactly English oo, but that is a useful approximation at first.

These are only approximations, but they are good enough to help you get started.

It depends on the noun’s grammatical gender.

Swedish nouns are usually either:

• common gender (en words)
• neuter (ett words)

Then the singular definite form is usually:

• en-word → -en
• ett-word → -et

In this sentence:

• en tjuv → tjuven
• ett hus → huset

So the key is to learn each noun together with its article:

• en tjuv
• ett hus

That makes it much easier to form the definite version later.