Penjual menjual barang bekas.

It follows the normal Indonesian Subject–Verb–Object order:

• Penjual = subject
• menjual = verb
• barang bekas = object

So structurally it is very similar to English Seller sells used goods.

They are closely related because they come from the same root, jual, which means to sell.

• menjual = to sell / sells
• penjual = seller / person who sells

So:

• meN- + jual → menjual = a verb
• peN- + jual → penjual = a noun for the person who does the action

This is a very common pattern in Indonesian, where related prefixes create a verb and an agent noun from the same root.

Because Indonesian often uses prefixes to show grammatical function.

The root is jual. Then:

• menjual is the active verb form
• penjual is the noun meaning seller

The prefixes help show whether the word is an action or a person.

In everyday speech, you may hear bare roots in some contexts, but in standard Indonesian menjual and penjual are the normal forms here.

Indonesian does not usually use articles the way English does.

So penjual could mean:

• a seller
• the seller
• sellers in a generic sense, depending on context

And barang bekas could mean:

• used goods
• the used goods
• some used goods

The exact meaning depends on the situation, not on an article.

In Indonesian, adjectives usually come after the noun.

So:

• barang bekas = used goods
• literally: goods used

That noun + adjective order is very normal in Indonesian.

Other examples:

• rumah besar = big house
• mobil baru = new car

Barang means goods, items, or things.
Bekas means used, secondhand, or sometimes former, depending on context.

So barang bekas means used goods or secondhand items.

In this sentence, bekas clearly describes barang, not penjual.

Yes. Bekas can have a few related meanings depending on context:

• used / secondhand
  
  • barang bekas = used goods
• former / ex-
  
  • bekas pacar = ex-boyfriend/ex-girlfriend
• mark / trace / scar
  
  • bekas luka = scar / mark of a wound

So learners often need context to know which meaning is intended. In barang bekas, the meaning is definitely used/secondhand.

Indonesian verbs do not change form for tense the way English verbs do.

So menjual by itself does not specifically mark present, past, or future. The time is usually understood from context or from time words such as:

• sekarang = now
• kemarin = yesterday
• besok = tomorrow

Without extra context, Penjual menjual barang bekas is usually read as a simple general statement like The seller sells used goods.

By itself, penjual does not clearly show singular or plural.

Depending on context, it could mean:

• a seller
• the seller
• sellers in a general sense

If you want to make plurality explicit, Indonesian can use reduplication or other words, for example:

• para penjual = the sellers
• penjual-penjual = sellers

But very often Indonesian leaves number unstated unless it matters.

Indonesian often does not need to mark plural if the meaning is already clear or generic.

So both of these can work:

• barang bekas
• barang-barang bekas

The first is very natural and can still mean used goods in a general sense. Reduplication is used when the speaker wants to emphasize plurality more clearly.

Because the sentence breaks naturally like this:

• Penjual = subject
• menjual = verb
• barang bekas = object

If you wanted seller of used goods, you would usually say:

• penjual barang bekas

That is a noun phrase meaning used-goods seller or seller of used goods.

But in your sentence, the presence of menjual makes it a full clause:
The seller sells used goods.

It is active.

The active verb is menjual, and the subject penjual is the one doing the action.

A passive version would look more like:

• Barang bekas dijual penjual.
• Barang bekas dijual oleh penjual.

Here dijual is the passive form, meaning is sold / are sold.

It is grammatical and understandable, but it also feels like a simple textbook-style sentence because it is very plain and generic.

In real life, people might say something more specific, such as:

• Penjual itu menjual barang bekas. = That seller sells used goods.
• Dia menjual barang-barang bekas. = He/She sells used items.
• Penjual ini menjual barang bekas murah. = This seller sells cheap used goods.

So the original sentence is correct, but it is especially useful as a clear grammar example.