Ta šala je bez veze.

Because šala is a feminine singular noun.

In Croatian, that changes form to match the gender, number, and case of the noun:

• taj = masculine singular
• ta = feminine singular
• to = neuter singular

Since šala is feminine, the correct form is ta.

Examples:

• taj film = that film
• ta šala = that joke
• to pitanje = that question

Šala is in the nominative singular.

This sentence is built like:

• Ta šala = the subject
• je = is
• bez veze = the predicate expression

In sentences with to be (biti), the subject usually stays in the nominative:

• Ta šala je...
• Ovaj film je...
• Ta knjiga je...

So šala is nominative because it is the thing being described.

Literally, bez veze means without connection or without relation.

But as an idiom, it usually means something like:

• pointless
• stupid
• lame
• nonsense
• it makes no sense

So in this sentence, bez veze is not being understood word-for-word only; it is a very common fixed expression.

Because the preposition bez always takes the genitive case.

The basic noun is:

• veza = connection, link, relationship

Its genitive singular is:

• veze

So:

• bez veze = without connection

This is a very common pattern in Croatian:

• bez šećera = without sugar
• bez vode = without water
• bez problema = without problems

So veze is there because bez requires genitive.

It is mostly colloquial/everyday language.

Native speakers use it very often in speech. It sounds natural and common, but not especially formal.

Depending on context, more formal or neutral alternatives could be:

• Ta šala nema smisla. = That joke makes no sense.
• Ta šala je besmislena. = That joke is senseless.
• Ta šala je glupa. = That joke is stupid.

So bez veze is very useful to know, but it has a conversational feel.

Because je is the 3rd person singular of biti (to be) and normally comes after the subject in a simple statement.

So the structure is:

• Ta šala = subject
• je = is
• bez veze = complement

This is the most neutral word order:

• Ta šala je bez veze.

Croatian word order is flexible, but this version is the standard, natural one for learners to use first.

You may also hear other orders for emphasis, but they are less neutral:

• Bez veze je ta šala.
  This can sound more marked or expressive.

Yes. That would mean This joke is lame/pointless.

The difference is:

• ta šala = that joke
• ova šala = this joke
• ona šala = that joke over there / that one

So the demonstrative changes depending on how near or far the thing feels to the speaker.

Very roughly:

• ova = this
• ta = that
• ona = that over there

No. It is extremely versatile.

You can use bez veze for many things:

• Film je bez veze. = The movie is lame / pointless.
• To je bez veze. = That’s pointless / stupid.
• Pitanje je bez veze. = The question is pointless.
• Pričaš bez veze. = You’re talking nonsense.

So it can describe:

• things
• situations
• comments
• actions
• even the way someone is speaking

That is one reason this expression is so common.

A simple learner-friendly pronunciation is:

ta SHA-la ye bez VE-ze

A few helpful points:

• š sounds like sh in shoe
• j sounds like y in yes
• ž does not appear here, but z in veze is just z
• Croatian pronunciation is usually quite phonetic, so words are pronounced close to how they are written

So:

• Ta = tah
• šala = SHA-la
• je = yeh
• bez veze = bez VE-ze

Yes. The words themselves are fairly common and not extremely rude, but tone matters a lot.

Depending on how you say it, it can sound:

• mildly dismissive
• annoyed
• sarcastic
• openly critical

Compared with stronger insults, bez veze is often relatively moderate. It is more like saying something is lame, pointless, or dumb than using a harsh swear word.

So it is a useful phrase, but you should still be aware that it can sound blunt if said directly about something another person said.