Kusen kayu itu cukup kuat.

Indonesian often leaves out the verb to be in simple descriptive sentences.

So instead of saying something like The wooden frame is quite strong, Indonesian simply says:

Kusen kayu itu cukup kuat
literally: that wooden frame quite strong

This is completely normal. In present-tense statements where you describe something, you usually do not need adalah or any other equivalent of is.

In Indonesian, adjectives usually come after the noun they describe.

So:

• rumah besar = big house
• meja kecil = small table
• kusen kayu itu cukup kuat = that wooden frame is quite strong

This is different from English, where adjectives usually come before the noun.

However, in this sentence, kuat is not directly inside the noun phrase. It is the main description of the whole subject:

• kusen kayu itu = the subject
• cukup kuat = the description

So the overall structure is:

[subject] + [description]

Yes, kayu is a noun meaning wood, but here it functions like a material modifier: wooden.

So:

• kusen = frame
• kayu = wood
• kusen kayu = wooden frame / wood frame

This is very common in Indonesian. A noun can modify another noun without changing form:

• meja kayu = wooden table
• pintu kaca = glass door
• sepatu kulit = leather shoes

So kayu is still basically a noun, but in this position it works like wooden in English.

In Indonesian, demonstratives like ini and itu usually come after the noun phrase.

So:

• rumah itu = that house
• mobil ini = this car
• kusen kayu itu = that wooden frame

This is the normal order. English says that wooden frame, but Indonesian says the equivalent of wooden frame that.

Also notice that itu comes after the whole noun phrase, not immediately after kusen:

• kusen kayu itu = that wooden frame
  not
• kusen itu kayu = that frame is wood / is made of wood

So word order matters.

Here, cukup means something like quite, fairly, or reasonably.

So cukup kuat means:

• quite strong
• fairly strong
• strong enough, depending on context

The exact feeling depends on the situation.

For example:

• If you are just describing quality, cukup kuat often sounds like quite strong or fairly strong.
• If you are evaluating whether it meets a need, it may feel more like strong enough.

So cukup can overlap with both ideas in English.

Not always.

Cukup is flexible. It can mean:

• enough
• quite
• fairly
• reasonably

So cukup kuat could mean:

• quite strong
• strong enough

The best translation depends on context.

If the sentence is just a neutral description, quite strong may fit better.
If someone is asking whether the frame can support something, strong enough may be better.

By itself, it is not marked clearly for number. Indonesian nouns are often number-neutral.

So kusen kayu itu could mean:

• that wooden frame
• those wooden frames

In many situations, context makes the number clear.
However, in everyday use, this phrase will often be understood as singular unless something suggests otherwise.

If you want to make plurality clearer, Indonesian can do that in other ways, such as context, numbers, or reduplication in some cases.

Yes, sometimes itu feels less strongly demonstrative than English that.

Depending on context, kusen kayu itu can mean:

• that wooden frame
• the wooden frame

In natural Indonesian, itu is often used to refer to something already known, identifiable, or previously mentioned. In those cases, English may translate it more naturally as the.

So while itu literally corresponds to that, its real use can overlap with English the in context.

Yes, you can.

Kusen kayu cukup kuat is grammatical and means Wooden frames are quite strong or A wooden frame is quite strong, depending on context.

Adding itu makes the noun phrase more specific:

• Kusen kayu cukup kuat = wooden frames / a wooden frame are/is quite strong
• Kusen kayu itu cukup kuat = that/the wooden frame is quite strong

So itu helps point to a particular frame.

No, not naturally.

Kusen kayu itu is understood as one noun phrase: that wooden frame.

So the structure is:

• kusen kayu itu = that wooden frame
• cukup kuat = quite strong

If you wanted to say That frame is made of wood and quite strong, you would usually make that clearer, for example with terbuat dari kayu or another more explicit structure.

So in this sentence, kayu belongs with kusen, not with the predicate.

Yes, kusen is a normal word, though it is more specific than very basic vocabulary. It usually refers to a frame, especially a door frame or window frame.

So kusen kayu would normally suggest a wooden door/window frame, not just any abstract frame.

The exact translation in English may vary depending on context:

• wooden frame
• wooden door frame
• wooden window frame

Yes.

• cukup kuat = quite strong / fairly strong / strong enough
• sangat kuat = very strong

So cukup gives a more moderate meaning, while sangat is stronger and more emphatic.

Compare:

• Kusen kayu itu cukup kuat. = That wooden frame is quite/fairly strong.
• Kusen kayu itu sangat kuat. = That wooden frame is very strong.

So cukup does not usually sound as strong as sangat.