Bloß weil's regnet, heißt das nicht, dass wir den Spieleabend absagen.

Bloß weil means just because. It adds emphasis and often suggests that the speaker is rejecting a conclusion someone might jump to.

So:

• weil es regnet = because it’s raining
• bloß weil es regnet = just because it’s raining

In this sentence, the tone is roughly: Just because it’s raining doesn’t mean we’re cancelling game night.

A very similar alternative is nur weil. In many contexts, bloß weil and nur weil are interchangeable.

Weil's is a contraction of weil es.

• weil es regnet
• weil's regnet

This is very common in spoken German and informal writing. It sounds natural and conversational.

If you want a more careful or formal written style, you would usually write weil es regnet instead of weil's regnet.

Because weil introduces a subordinate clause, and in German subordinate clauses the conjugated verb usually goes to the end.

So:

• main clause: Es regnet.
• subordinate clause: weil es regnet

That is why you get weil's regnet, not weil's regnet es or weil regnet's.

Because the sentence begins with a subordinate clause: Bloß weil's regnet. That whole clause takes the first position in the sentence.

In German main clauses, the finite verb must be in second position. So after that first-position element, the verb comes immediately:

• Bloß weil's regnet, heißt das nicht, ...

If you put the clauses in a more basic order, you can see it more clearly:

• Das heißt nicht, dass wir den Spieleabend absagen, bloß weil's regnet.

So the verb-first feeling in heißt das nicht is just normal German verb-second word order after a fronted clause.

Literally, it means that does not mean.

German often uses das heißt in the sense of that means. Here it is negated:

• heißt das nicht = that does not mean

So the structure is:

• Bloß weil's regnet = Just because it’s raining
• heißt das nicht = that doesn’t mean
• dass wir den Spieleabend absagen = that we’re cancelling game night

Das refers forward to the idea in the following dass clause.

In other words, das stands for the conclusion someone might draw, namely:

• dass wir den Spieleabend absagen

So Das heißt nicht, dass ... is a very common pattern meaning:

• That does not mean that ...

English often uses a dummy that or just leaves things looser, but German commonly includes das here.

Because heißen in this pattern often introduces the content of what something means by using dass.

So:

• Das heißt nicht, dass ... = That doesn’t mean that ...

The dass clause gives the actual idea being rejected:

• dass wir den Spieleabend absagen

This is very natural German. You could think of it as: It does not mean this: that we are cancelling game night.

Because absagen is a separable verb: absagen = to cancel.

In a normal main clause, separable verbs split:

• Wir sagen den Spieleabend ab.

But in an infinitive or in a subordinate clause, the verb stays together and goes to the end:

• ..., dass wir den Spieleabend absagen.

So this is exactly what you should expect inside a dass clause.

Because absagen takes a direct object in the accusative case.

The noun der Spieleabend is masculine, so:

• nominative: der Spieleabend
• accusative: den Spieleabend

Compare:

• Der Spieleabend ist heute.
  Here it is the subject, so nominative.

• Wir sagen den Spieleabend ab.
  Here it is the direct object, so accusative.

Yes. Spieleabend is a compound noun:

• Spiele = games
• Abend = evening

Together, Spieleabend means something like game night or games evening.

German forms compounds very freely, so it is completely normal to combine nouns like this into one word.

Yes, that is a perfectly natural alternative, but it means something slightly different in structure and emphasis.

• Bloß weil's regnet, heißt das nicht, dass wir den Spieleabend absagen.
  = Just because it’s raining doesn’t mean we’re cancelling game night.

• Nur weil es regnet, sagen wir den Spieleabend nicht ab.
  = We’re not cancelling game night just because it’s raining.

The first version explicitly rejects a conclusion. The second more directly states what you are not doing. Both are idiomatic.

It often adds emphasis and can sound a little defensive, impatient, or corrective depending on context.

Here it suggests something like:

• Don’t jump to conclusions.
• Rain alone is not enough reason to cancel.

So it is not overly dramatic, but it is stronger than plain weil. It gives the sentence a more spoken, expressive feel.

Yes.

German normally uses commas to separate subordinate clauses from main clauses, and also before dass clauses.

So in:

• Bloß weil's regnet, heißt das nicht, dass wir den Spieleabend absagen.

the commas mark:

1. the end of the weil clause
2. the start of the dass clause

They are not optional in standard writing.

It is basically standard German, but with one slightly informal feature:

• weil's instead of weil es

Everything else is fully standard. If you wanted a more neutral written version, you could write:

• Bloß weil es regnet, heißt das nicht, dass wir den Spieleabend absagen.

That version would fit standard formal writing more comfortably.