Non toccare l'arma.

Because in Italian, a negative command to one person you address as tu is usually formed with:

non + infinitive

So:

• Tocca! = Touch!
• Non toccare! = Don’t touch!

This is one of the first command patterns learners notice, because it does not use the usual tu imperative in the negative.

It normally speaks to one person informally: you (singular, informal).

Compare:

• Non toccare l'arma. = don’t touch the weapon. (to one person, informal)
• Non toccate l'arma. = don’t touch the weapon. (to more than one person)
• Non tocchi l'arma. = don’t touch the weapon. (formal singular)

So this sentence is the version you would use with one person you address as tu.

Non is the standard Italian word for not. It goes before the verb and makes the sentence negative.

Examples:

• Toccare l'arma = to touch the weapon
• Non toccare l'arma = not to touch / don’t touch the weapon

In commands, non simply turns the instruction into a prohibition.

Because arma begins with a vowel, and the feminine singular definite article la usually becomes l' before a vowel.

So:

• la penna
• la casa
• l'arma
• l'acqua

This shortening is called elision.

So la arma is not the normal form; l'arma is the correct one.

Because arma is simply a feminine noun in Italian. Noun gender in Italian is something you usually have to learn with the word.

So you get:

• l'arma = the weapon
• un'arma = a weapon
• le armi = the weapons

Even if the object itself has no biological gender, the noun still has grammatical gender.

Literally, l'arma is the weapon because l' is the definite article.

However, in real usage, Italian often uses the definite article in places where English might sound more natural with the, that, or sometimes a more context-based translation.

Depending on context, it could refer to:

• a specific weapon already known in the situation
• the weapon someone is holding
• the weapon in front of the speaker and listener

If Italian wanted to say a weapon, it would normally use:

• un'arma

So the sentence with the article is definitely definite in form.

Arma is the broader word weapon. Depending on context, English might translate it as:

• weapon
• sometimes gun, if it is clear that the object is a firearm

But by itself, arma does not specifically mean only gun.
If you want to be more specific, Italian might use words like:

• pistola = pistol
• fucile = rifle
• arma da fuoco = firearm

So Non toccare l'arma is best understood literally as Don’t touch the weapon unless context makes gun more natural.

Toccare is perfectly normal and means to touch.

So Non toccare l'arma is a direct and natural warning: Don’t touch the weapon.

That said, if the speaker specifically means don’t handle it / don’t mess with it, Italian might also use verbs such as:

• non maneggiare l'arma = don’t handle the weapon
• non usare l'arma = don’t use the weapon

So toccare focuses on physical contact: don’t touch.

A helpful approximation is:

non tohk-KAH-reh LAR-ma

A few key points:

• toccare has a doubled cc, pronounced like a strong k sound: tok-KAH-re
• the stress is on -ca-: tocCAre
• l'arma is said smoothly together, almost like larma

So the flow is:

Non toccare l'arma.

Yes. If the object is obvious from context, Italian can absolutely omit it.

• Non toccare! = Don’t touch!
• Non toccare l'arma! = Don’t touch the weapon!

Adding l'arma makes the warning more specific. Omitting it makes it broader or more situational.

The positive informal singular command would be:

Tocca l'arma. = Touch the weapon.

This contrast is useful:

• Tocca l'arma. = touch the weapon
• Non toccare l'arma. = don’t touch the weapon

So the positive tu command uses tocca, but the negative tu command uses non toccare. That contrast is very important in Italian.