Tukang bangunan mengaci dinding.

Tukang bangunan means construction worker, builder, or workman.

• tukang often means a skilled worker, tradesperson, or someone who does a certain job
• bangunan means building or construction

So together, tukang bangunan refers to someone who does construction work.

In Indonesian, it is very common to make noun phrases by putting two nouns together.

Here:

• tukang = worker/craftsman
• bangunan = building/construction

So tukang bangunan literally means something like building worker.

This is normal Indonesian word formation. English often uses a similar idea too, like construction worker or office worker.

Mengaci means to apply a smooth finishing layer of plaster/cement to a wall.

It is a specific construction verb. It does not just mean to build or to paint. It refers to smoothing or finishing a wall surface, usually with cement or plaster.

So in this sentence, the worker is doing a finishing job on the wall.

The prefix meng- is a very common Indonesian verb prefix. It often forms an active transitive verb, meaning a verb where the subject does something to an object.

In this sentence:

• mengaci = to plaster/smooth-finish something
• dinding = wall

So the pattern is:

Subject + active verb + object

• Tukang bangunan = subject
• mengaci = verb
• dinding = object

The prefix meng- is part of standard Indonesian verb formation.

Yes. The base form is aci.

Then:

• aci = plaster/smoothing material, or the root idea related to that finishing process
• mengaci = to apply that material / to plaster-smooth a surface

So mengaci is the verb form built from aci.

Because Indonesian commonly uses Subject + Verb + Object, just like English.

So:

• Tukang bangunan = the construction worker
• mengaci = plasters / is plastering
• dinding = the wall

That makes the sentence very straightforward for English speakers: The construction worker plasters the wall.

Indonesian usually does not use articles like a, an, or the.

So:

• tukang bangunan can mean a construction worker or the construction worker
• dinding can mean a wall or the wall

The exact meaning depends on context.

That means Tukang bangunan mengaci dinding could be understood as:

• A construction worker is plastering a wall
• The construction worker is plastering the wall

Context tells you which one is meant.

No, not by itself.

Indonesian verbs do not change form for tense the way English verbs do. Mengaci can mean:

• plasters
• is plastering
• plastered
• will plaster

depending on context.

If you want to make time clearer, Indonesian often adds time words such as:

• sedang = currently/in the process of
• tadi = earlier
• kemarin = yesterday
• besok = tomorrow

For example:

• Tukang bangunan sedang mengaci dinding. = The construction worker is plastering the wall.

Dinding means wall.

It is often used for a wall as part of a room or building structure.
Tembok also means wall, but it often suggests a more solid wall, outer wall, or masonry wall.

In many everyday situations, the two words may overlap, but dinding is a very natural choice here because this is a construction/finishing context involving a wall surface.

A rough pronunciation is:

mengaci ≈ meng-AH-chee

Notes:

• ng is like the sound in English sing
• c in Indonesian is pronounced like ch in English chair
• the stress is usually not as strong or dramatic as in English, but ga is often said clearly

So:

• me-nga-ci
• not men-gay-see
• not men-ka-see

Yes. Pekerja bangunan also means construction worker.

The difference is mainly nuance:

• tukang bangunan sounds very common and natural in everyday speech
• pekerja bangunan is also correct, and can sound a bit more formal or neutral

So both are fine, but tukang bangunan is very natural in this kind of sentence.

Yes, if the context is already clear.

For example:

• Tukang bangunan sedang mengaci.
  = The construction worker is plastering / doing the plaster finish.

But if you want to say exactly what is being plastered, you include the object:

• Tukang bangunan mengaci dinding.

So the full sentence is clearer, especially for learners.

A natural passive version is:

Dinding diaci oleh tukang bangunan.

This means: The wall is plastered by the construction worker.

Notes:

• active: Tukang bangunan mengaci dinding
• passive: Dinding diaci oleh tukang bangunan

In Indonesian, passive voice is very common, often more common than in English.

Yes, it is complete, grammatical, and natural.

It has everything needed:

• subject: tukang bangunan
• verb: mengaci
• object: dinding

It sounds like a normal textbook-style example sentence describing an action in construction work.