Mereka mahu keamanan.

Mereka is the third-person plural pronoun, so in this sentence it means they.

A few useful points:

• It refers to people, not usually things.
• Malay pronouns do not show gender, so mereka can mean they for any group of people.
• The same form can also correspond to English them in other sentence patterns, because Malay does not change pronouns the way English does for subject/object case.

In Mereka mahu keamanan, mereka is the subject, so they is the natural English match.

Yes. Mahu means want or wish to.

It is a very common and standard Malay word. You may also see:

• hendak – often a bit more formal or careful
• ingin – often closer to desire or wish
• nak – very common in speech, more informal, a shortened form of hendak

So:

• Mereka mahu keamanan = standard and natural
• Mereka nak keamanan = more colloquial

Because aman and keamanan are different kinds of words.

• aman is an adjective: peaceful, safe, secure
• keamanan is a noun: peace, security

So:

• negara aman = a peaceful country
• mahu keamanan = want peace

The word keamanan is formed from aman with the pattern ke-...-an, which often creates an abstract noun in Malay.

It can mean either, depending on context.

From aman, which has the sense of being safe, peaceful, or secure, keamanan can refer to:

• peace
• security
• public order / safety

In a sentence like Mereka mahu keamanan, the most natural meaning is often They want peace, but They want security could also fit in the right context.

Yes, it is the basic subject + verb + object order:

• Mereka = subject
• mahu = verb
• keamanan = object

So the structure is very similar to English:

• They want peace

This is one reason simple Malay sentences can feel quite accessible to English speakers.

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

So keamanan can simply mean:

• peace
• the peace
• sometimes a state of peace, depending on context

Malay relies much more on context than English does for this kind of meaning.

Malay verbs do not usually change form for tense the way English verbs do.

So mahu stays mahu whether the meaning is present, past, or future. The time is understood from context or shown with time words such as:

• semalam = yesterday
• sekarang = now
• esok = tomorrow
• akan = will / going to

By itself, Mereka mahu keamanan is most naturally understood as a present or general statement:

• They want peace
• They desire peace

It is basically neutral standard Malay.

• mereka is standard
• mahu is standard
• keamanan is a fairly formal or elevated noun compared with very everyday speech

So the whole sentence sounds natural in writing, news, public statements, and general standard usage. In casual conversation, someone might say:

• Mereka nak keamanan

That version is more conversational, but the original sentence is completely normal.

Sometimes, yes. Malay often allows subjects to be omitted when they are understood from context.

For example, if everyone already knows who is being discussed, someone might simply say:

• Mahu keamanan

However, in a standalone sentence, Mereka mahu keamanan is clearer and more complete.

Yes, the plurality comes from mereka itself.

Malay nouns often do not change form for singular vs. plural, and verbs do not change either. But mereka specifically means a plural group of people, so that is what tells us the subject is they.

By contrast:

• dia mahu keamanan = he/she wants peace
• mereka mahu keamanan = they want peace