Negative Imperative: ～な (na)

You are going to love the logic here. Most Japanese grammar involves chopping off verb stems and juggling endings. Not this one. To form the negative imperative, you take the dictionary form of any verb and just slap な onto the end. That is it. No changes to the verb itself. It does not matter if it is a Group 1, Group 2, or an irregular verb. The dictionary form stays perfectly intact. This simplicity reflects the nature of the command: it is meant to be yelled quickly in a crisis. You don't have time to conjugate when a piano is falling from a window, right? Just remember that this な is different from the friendly な used at the end of sentences to mean "isn't it?" The tone and the grammar structure make the difference obvious.

1. 1Setting this up is a three-step process that takes about two seconds to master.
2. 2Identify the Dictionary Form (also called the plain form) of the verb.
3. 3Add the particle な immediately after the verb.
4. 4Stop right there. Do not add です or anything else.
5. 5Let’s look at some quick transformations:
6. 6食べる (taberu - to eat) becomes 食べるな (taberuna - Don't eat!).
7. 7行く (iku - to go) becomes 行くな (ikuna - Don't go!).
8. 8する (suru - to do) becomes するな (suruna - Don't do it!).
9. 9来る (kuru - to come) becomes 来るな (kuruna - Don't come!).
10. 10Yes, even the irregulars する and 来る follow the same easy rule. It’s like a grammar holiday.

Context is everything with this rule. Since it is incredibly strong, you need to know when it is actually appropriate.

• Emergencies: If you see someone about to step into traffic, scream 見るな! (Don't look!) or 動くな! (Don't move!). Politeness takes a backseat when lives are on the line.
• Signage: You will see this on "No Entry" signs (入るな) or "Don't Litter" posters. It is used in writing because it is space-efficient and authoritative.
• Angry Authority: A father might tell his child 泣くな (Don't cry) in a stern voice. A coach might yell 諦めるな (Don't give up) during a match.
• Close Male Friends: In very informal settings, guys might use it for a rough, brotherly vibe. "Don't say that!" might become 言うなよ (the よ softens it slightly).
• Internal Monologue: When you are telling yourself not to mess up, you might think 失敗するな (Don't fail).

If you want to keep your friends and your job, pay attention here.

• Service Industry: Never use this when ordering food. 食べるな to a waiter is a great way to get kicked out.
• Workplace: Do not use this with your boss or colleagues. Even if they are doing something wrong, use the polite ～ないでください form.
• Strangers: Unless you are saving their life, using な with a stranger is extremely offensive. It sounds like you are talking down to them.
• First Dates: Unless the date is going horribly and you want it to end immediately, avoid this command. It is not "cool" blunt; it is "mean" blunt. Think of it like a grammar traffic light: if you aren't in a "Red Alert" situation, keep this tool in your pocket.

The most frequent trip-up is confusing this command with the sentence-ending particle な.

• Mistake 1: Using the Masu-stem. People often try to say 飲みな (nomina) thinking it means "Don't drink." Actually, Stem + な is often a shortened version of なさい, which is a *positive* command (Eat up! Drink up!). The negative MUST use the full dictionary form: 飲むな.
• Mistake 2: Ignoring Intonation. The command な is usually short and falling. The friendly "isn't it" な is usually drawn out or rising.
• Mistake 3: Overusing it. Many learners hear this in anime and think it sounds cool. In real-life Japan, using it too much makes you sound like a cartoon villain or someone who never learned manners.

Let’s compare the "Don'ts" of Japanese so you can choose the right one.

• ～ないでください (naide kudasai): The gold standard. Polite, safe, and works everywhere from the office to the supermarket.
• ～ないで (naide): The casual version. Great for friends and family. "Don't do that, okay?"
• ～な (na): The command. Blunt, masculine, and forceful. "Stop. Now."
• ～だめ (dame): More like saying "That is no good." It is common in casual speech but doesn't have the "command" energy of な.
• ～てはいけません (te wa ikemasen): Formal prohibition. You’ll hear this in schools or read it in manuals. It is more about "rules" than "commands."