Kalau hujan deras, rapat bisa ditunda.

Kalau means if or sometimes when in everyday Indonesian. It introduces the condition:

• Kalau hujan deras = If it rains heavily / If there is heavy rain

Starting with the condition is very common in Indonesian, just like in English:

• If it rains heavily, the meeting can be postponed.

You could also put the main clause first in Indonesian, but this version is very natural.

Hujan means rain, and deras means heavy or intense when talking about rain or water flow.

So:

• hujan deras = heavy rain

Indonesian often puts descriptive words after the noun, so this is different from English word order:

• English: heavy rain
• Indonesian: rain heavy → hujan deras

Indonesian often leaves out subjects when they are not needed.

In English, you must say:

• If it rains heavily

But in Indonesian, you can simply say:

• Kalau hujan deras

There is no need for a dummy subject like it. This is very normal in Indonesian weather expressions.

The comma separates the condition from the main result:

• Kalau hujan deras, = condition
• rapat bisa ditunda. = result

This works much like English:

• If it rains heavily, the meeting can be postponed.

In informal writing, people sometimes omit commas, but using one here is clear and standard.

Here, rapat means meeting.

This word can also appear in other contexts, and in some cases it can mean close/tight, but in this sentence the meaning is clearly meeting because of the context:

• rapat bisa ditunda = the meeting can be postponed

Context is very important in Indonesian because many words have more than one meaning.

Bisa usually means can, be able to, or it is possible to.

In this sentence:

• rapat bisa ditunda = the meeting can be postponed / the meeting may be postponed

It does not necessarily mean that the postponement will happen. It means it is possible or allowed, depending on context.

A small warning: bisa can also mean venom/poison in other contexts, but not here.

Ditunda is the passive form of the verb tunda (to postpone).

• tunda = postpone
• ditunda = be postponed

The prefix di- often marks passive voice in Indonesian. So:

• Rapat ditunda = The meeting is postponed / was postponed
• Rapat bisa ditunda = The meeting can be postponed

This is very common when the thing affected by the action is the topic of the sentence.

Indonesian often uses the passive when the doer is unknown, unimportant, or obvious from context.

So rapat bisa ditunda focuses on the meeting, not on the person who postpones it.

English often does the same:

• The meeting can be postponed

If you wanted to mention the person or group doing it, you could add that separately, but it is not necessary here.

No. Kalau is very common and natural in everyday speech and writing, but there are other options.

For example:

• jika = if (more formal)
• bila = if/when (often a bit more formal or literary)

So you might also see:

• Jika hujan deras, rapat bisa ditunda.

That means basically the same thing, but kalau sounds more conversational.

Sometimes yes, depending on context. Kalau can introduce a condition or a situation that happens regularly.

But in this sentence, it is most naturally understood as if:

• If there is heavy rain, the meeting can be postponed.

If the speaker meant a repeated situation, English might translate it more like:

• When it rains heavily, the meeting can be postponed.

So the exact nuance depends on context, but if is the safest interpretation here.

Yes. Indonesian does not mark tense the way English does, so bisa ditunda is flexible.

Depending on context, it could be translated as:

• can be postponed
• could be postponed
• may be postponed

The sentence itself does not tell you past, present, or future. Time usually comes from context or time words such as besok, tadi, or nanti.

Yes, they might, but it has a slightly different feel.

• Kalau hujan deras = a general, simple statement
• Kalau hujannya deras = if the rain is heavy / if the rainfall is heavy

The ending -nya can make hujan feel more specific or definite in context. Both are possible, but kalau hujan deras is very straightforward and natural.

It is neutral and natural. It is not slangy, but it is also not overly formal.

• kalau makes it sound everyday and conversational
• the structure itself is standard and widely acceptable

In a more formal context, you might see:

• Jika hujan deras, rapat dapat ditunda.

Here jika and dapat sound more formal than kalau and bisa. But the original sentence is perfectly normal Indonesian.