Večeře zatím není hotová.

Here zatím means for now / so far / yet in the sense of up to this point.

So Večeře zatím není hotová means something like:

• Dinner isn’t ready yet
• So far, dinner isn’t ready

It is similar to ještě in many situations, and learners often compare these:

• Večeře ještě není hotová. = Dinner isn’t ready yet.
• Večeře zatím není hotová. = Dinner isn’t ready yet / so far dinner isn’t ready.

A useful difference:

• ještě often simply means still / yet
• zatím often suggests for the time being / up to now

In this sentence, both are natural, but zatím can sound a little more like at the moment or so far.

In Czech, negation is usually built directly into the verb.
The verb je (is) becomes není (is not).

So:

• je = is
• není = is not

You do not normally add a separate word like English not after the verb. Czech uses the negative form of the verb itself.

Examples:

• To je dobré. = That is good.
• To není dobré. = That is not good.

So Večeře zatím není hotová is structurally normal Czech.

Because hotová agrees with večeře, which is a feminine singular noun.

In Czech, adjectives often change their endings to match the noun’s:

• gender
• number
• case

Here:

• večeře = feminine singular
• therefore the adjective is hotová = feminine singular

Compare:

• oběd není hotový = lunch is not ready
  (oběd is masculine)
• večeře není hotová = dinner is not ready
  (večeře is feminine)
• jídlo není hotové = food is not ready
  (jídlo is neuter)

So the ending is there because of grammatical agreement.

Because večeře is simply a noun that belongs to the feminine grammatical gender in Czech.

This is grammatical gender, not biological gender. Objects and abstract things also have gender in Czech.

Many Czech nouns ending in -e can be feminine, and večeře is one of them.

You just need to learn it as part of the noun:

• ta večeře = the dinner/supper (feminine)

That matters because other words will agree with it:

• ta večeře
• večeře je hotová
• bez večeře

Yes, večeře is the subject of the sentence, and it is in the nominative singular.

The basic structure is:

• Večeře = subject
• není = verb
• hotová = predicate adjective / complement
• zatím = adverb

So literally:

• Dinner for now is-not ready

Because večeře is the subject, it appears in the nominative form.

Yes. Czech word order is fairly flexible, and changing it can shift the emphasis.

The neutral version is:

• Večeře zatím není hotová.

Other possible versions:

• Zatím večeře není hotová.
• Večeře není zatím hotová.

These all mean roughly the same thing, but the focus changes slightly:

• starting with Večeře emphasizes dinner
• starting with Zatím emphasizes for now / at the moment

For a learner, Večeře zatím není hotová is a very natural and safe word order.

It can mean both, depending on context.

In this sentence, hotová most naturally means:

• ready
• done
• possibly finished cooking / prepared

So Večeře zatím není hotová usually means dinner is not prepared yet or not ready to be served.

In other contexts, hotový / hotová / hotové can also mean:

• finished
• completed
• done

Examples:

• Práce je hotová. = The work is finished.
• Jsem hotový. = literally I’m done, sometimes even I’m exhausted in colloquial use.

So the exact shade of meaning depends on what is being talked about.

Yes, absolutely. That is very common and natural.

• Večeře ještě není hotová. = Dinner isn’t ready yet.
• Večeře zatím není hotová. = Dinner isn’t ready yet / so far dinner isn’t ready.

Both are correct.
If you are unsure which to use, ještě is probably the more direct equivalent of English yet.

It can correspond to either dinner or supper, depending on the speaker and the variety of English.

In Czech, večeře is the evening meal.
So the best English translation depends on the learner’s dialect and habits:

• for many speakers: dinner
• for others: supper

That is a translation issue, not a grammar issue.

Usually not in this sentence, if you want to say specifically that dinner is not ready.

Czech often omits subject pronouns like já, ty, on, because the verb form already shows the person:

• Nejsem připravený. = I’m not ready.

But here the noun večeře carries important information.
If you remove it and just say:

• Zatím není hotová.

that can still be grammatical, but only if the listener already knows what she/it refers to from context. The adjective hotová is feminine, so something feminine is understood, but without context it sounds incomplete.

So in isolation, keeping večeře is best.

Because Czech has no articles like English a / an / the.

So večeře can mean:

• dinner
• the dinner
• sometimes even a dinner

The exact meaning depends on context.

That is why a short Czech sentence may correspond to several English versions:

• Dinner isn’t ready yet.
• The dinner isn’t ready yet.

English must choose an article or go without one depending on the noun, but Czech does not.