ممنوع اللمس هنا.

Because Arabic often uses a nominal sentence in the present tense, with no written or spoken word for is/are.

So ممنوع اللمس هنا is understood as:

Touching is forbidden here
or
It is forbidden to touch here

This is especially common in signs and notices, where Arabic is often short and compact.

ممنوع means forbidden, prohibited, or not allowed.

It comes from the verb مَنَعَ meaning to prevent or to forbid.
Grammatically, ممنوع is a passive participle, so its basic sense is something that has been forbidden.

On signs, ممنوع is extremely common and works almost like a fixed warning word:

• ممنوع التدخين = No smoking
• ممنوع الدخول = No entry
• ممنوع التصوير = No photography

No. اللمس is a noun, specifically a verbal noun (called a maṣdar in Arabic).

It comes from the verb لَمَسَ = to touch.
So اللمس means touching or the act of touching.

English often uses to touch or touching, but Arabic very often uses this kind of verbal noun instead.

The الـ makes it definite, but in expressions like this it often refers to the action in a general sense:

اللمس = touching as an activity/category

This is very common on signs. Arabic often uses the definite form for general activities:

• التدخين = smoking
• الدخول = الدخول / entering
• الوقوف = standing / parking

So here, اللمس does not mean one specific touch. It means touching in general.

Both are understandable, but they feel slightly different.

• اللمس ممنوع هنا is a more regular full sentence: Touching is forbidden here
• ممنوع اللمس هنا is a very common sign style or notice style

Putting ممنوع first makes the warning more immediate. It is similar to how signs in English often use compressed wording instead of full sentences.

They are close in meaning, but not identical in tone.

• لا تلمس هنا = Don’t touch here
  This directly addresses one person.

• ممنوع اللمس هنا = Touching is prohibited here
  This is more impersonal and sounds like a public notice or rule.

So if you are speaking directly to someone, لا تلمس is more natural.
If you are writing a sign, ممنوع اللمس is very natural.

Usually, no.

On signs, labels, and most everyday written Arabic, case endings are not written, so learners normally read it simply as:

ممنوع اللمس هنا

In very careful fully vocalized Arabic, a fuller sentence could be:

اللَّمْسُ مَمْنُوعٌ هُنَا

But for practical reading, especially on signs, you do not need to add endings in your head unless you are specifically studying grammar.

A helpful pronunciation is:

mamnūʿ al-lams hunā

Roughly:

mam-NOOʿ al-LAMS hoo-NAA

A few notes:

• ممنوع ends with ع (ʿayn), which is a throat sound that English does not have.
• In اللمس, the l sound is doubled in actual pronunciation, because the article joins with another l.

So if you want a slightly more accurate sound, it is close to:

mamnūʿ allams hunā

Yes. هنا means here, and Arabic allows some flexibility in word order.

Possible arrangements include:

• ممنوع اللمس هنا
• اللمس ممنوع هنا
• هنا ممنوع اللمس

They all keep the basic meaning, but the most natural form for a sign is the original one:

ممنوع اللمس هنا

Yes — very much so. This is one of the most useful sign patterns in Modern Standard Arabic.

You can reuse ممنوع + verbal noun with many actions:

• ممنوع التدخين = No smoking
• ممنوع الدخول = No entry
• ممنوع الوقوف = No parking / standing prohibited
• ممنوع التصوير = No photography
• ممنوع الكلام = Talking is not allowed

So ممنوع اللمس is part of a very productive and common pattern.

Usually it means touching in a general sense, often physical contact by hand, but the exact scope depends on context.

On a sign, ممنوع اللمس is normally understood broadly as:

Do not touch this / No touching

So the important idea is physical contact is not allowed, not a very narrow technical definition of touch.