Prohibitive Form: How to Say 'Don't'

Meaning & Usage

禁止形（禁止きんし形けい）— the prohibitive form — strips prohibition down to its bare minimum. Attach the particle な to any verb's plain dictionary form（辞書形じしょけい）and you have a blunt command: "Don't do ~!" 行いく（to go）becomes 行いくな（Don't go!）, 食たべる（to eat）becomes 食たべるな（Don't eat!）. Nothing could be simpler.

Simple in structure, but sharp in tone. 禁止形 hits like a verbal stop sign — closer to a drill sergeant barking "Don't move!" than a friend saying "Please don't do that." Use it at the wrong moment and the result ranges from awkward to outright rude.

In contemporary Japanese, 禁止形 is considered rough speech（荒あらい言葉ことば）. In polite, everyday conversation, Japanese speakers almost always choose softer alternatives:

• 〜ないでください — "Please don't..." (polite, formal)
• 〜ないで — "Don't..." (casual but gentle)
• 〜てはいけない / 〜てはだめ — "You must not..." (rule-based prohibition)
• 〜てはならない — "One must not..." (formal, written)

So when do native speakers actually use 禁止形? It appears most naturally in the following situations:

• 権威者けんいしゃから部下ぶかへ — Authority figures speaking to subordinates: coaches yelling at players, senior military personnel giving orders, strict parents disciplining children
• 緊急きんきゅう事態じたい — Emergency situations where there is no time for politeness（動うごくな！— "Don't move!"）
• マンガ・アニメ・劇的げきてきな場面ばめん — Manga, anime, and dramatic fiction, where 禁止形 carries emotional force
• 励はげましのことば・名言めいげん — Motivational set phrases, such as 諦あきらめるな（Don't give up）
• 看板かんばん・掲示けいじ — Written signs and notices, though formal written prohibitions more often use 〜べからず（archaic）or 〜禁止きんし

Picture it as a verbal stop sign. The verb arrives in its most basic form — no softening, no politeness markers — and な lands at the end like a sudden brake. No ambiguity, no negotiation: stop that action, right now.

At N3, 禁止形 matters more for recognition than production. Novels, manga, films, news — authentic Japanese is full of it. Miss it and you'll misread the emotional charge of an entire scene.

Structure & Formation

禁止形 follows the same rule for every verb type — no exceptions. Group 1（う動詞どうし）, Group 2（る動詞どうし）, irregular verbs: the formula never changes.

動詞どうし（辞書形じしょけい） ＋ な

重要じゅうよう: 禁止形 can only be formed from verbs. You cannot attach prohibitive な directly to adjectives or nouns to create a prohibition.

Note also that the な in 禁止形 is written in hiragana and spoken with a falling or flat intonation. This is critical for distinguishing it from the な in な-adjectives (e.g., 静しずかな — quiet) and the sentence-final な used to express emotion or seek agreement (e.g., 寒さむいな — "It's cold, isn't it").

Example Sentences

基本的きほんてきな禁止きんし（Basic Prohibitions）

緊急きんきゅう・警告けいこく（Emergency and Warnings）

感情的かんじょうてきな表現ひょうげん（Emotional Expressions）

励はげましと動機付どうきづけ（Encouragement and Motivation）

日常的にちじょうてきな指示しじ（Everyday Directives）

Common Mistakes

Mistake 1: Using 禁止形 in Polite Conversation

❌ 先生せんせい、廊下ろうかで走はしるな。

✅ 先生せんせい、廊下ろうかで走はしらないでください。

The 禁止形 is too blunt and aggressive for polite situations. Using it toward a teacher, a customer, or anyone above you in the social hierarchy is extremely rude. In formal or polite contexts, always use 〜ないでください. Reserve 禁止形 for emergencies, authority-to-subordinate commands, or dramatic contexts where directness is deliberate.

Mistake 2: Confusing 禁止の な with Sentence-Final な

❌ (Reading) 寒さむいな as a prohibition ✅ 寒さむいな = "It's cold, isn't it?" (observation); 入はいるな = "Don't enter!" (prohibition)

Japanese has two very different sentence-final な particles. The 禁止の な follows a verb in dictionary form and commands someone NOT to do something. The 終助詞の な follows adjectives, past forms, or nouns and expresses feelings, observation, or agreement. Your key diagnostic: check what precedes な. Dictionary-form verb like 行いく or 食たべる? Almost certainly a prohibition. Adjective or past-tense verb? The emotional particle.

Mistake 3: Attaching な to the Negative Form

❌ 食たべないな → (This is NOT a prohibition meaning "Don't not eat")

✅ 食たべるな → "Don't eat!" (prohibition)

Some learners add な to the negative ない form, reasoning that a double negative creates emphasis. It doesn't. 食たべないな means "He/she doesn't eat, huh" — an observation, not a command. Prohibition always uses the plain affirmative dictionary form. This is one of the most common errors at the intermediate level.

Mistake 4: Using 禁止形 with Adjectives or Nouns

❌ 静しずかな！（intending to mean "Don't be quiet!"）

✅ 静しずかにするな。（"Don't stay quiet! / Don't act quietly!"）

禁止形 is exclusively a verbal construction. To prohibit a state described by a な-adjective, first convert it into a verbal phrase using する — for example, 静しずかにする（to be quiet）— then apply prohibitive な: 静しずかにするな. The な in 静しずかな is adjectival, not prohibitive.

Mistake 5: Overusing 禁止形 in Everyday Casual Speech

❌ Using 行いくな or 食たべるな casually with classmates or colleagues in ordinary conversation ✅ 行いかないで、食たべないで (casual); 行いかないでください、食たべないでください (polite)

Even among close friends, repeated 禁止形 sounds bossy or unnecessarily masculine. Contemporary young Japanese — particularly women — almost never use it in everyday conversation; they reach for 〜ないで instead. Overuse will make you sound like an anime character or a 1970s yakuza. Save it for genuine urgency or when an authoritative tone is deliberate.

Cultural Notes

The 禁止形 has deep roots in traditional Japanese culture, where clear hierarchical relationships made direct commands from superiors to subordinates normal and expected. A 侍さむらい（samurai）commander, an 親方おやかた（master craftsman）directing apprentices, a strict Meiji-era schoolteacher — all would have used 禁止形 naturally and frequently.

In contemporary Japan, however, the social landscape has shifted. Flatter hierarchies in modern workplaces, a greater emphasis on harmony（和わ）, and changing norms around gender expression have pushed 禁止形 into more restricted domains. Today it is most strongly associated with 男性語だんせいご（masculine speech）, particularly the language of older men. Young men who use it heavily may sound outdated, overly aggressive, or as if they are performing a tough-guy persona from a 1970s yakuza film.

Sports is where 禁止形 still feels completely at home. Baseball coaches, soccer managers, martial arts sensei — all push their players with commands like 手てを抜ぬくな（Don't cut corners）, 諦あきらめるな（Don't give up）, 負まけるな（Don't lose）. The form carries weight: discipline, high standards, belief in the athlete.

Manga and anime run on 禁止形. Heroes in crisis, villains issuing cold threats, coaches before the final match, mentors pushing young protagonists — the form drives emotional impact. A character screaming 死しぬな！（Don't die!）at a fallen ally hits with a rawness that 死しなないでください simply cannot deliver. Catch that difference and your reading of authentic Japanese deepens immediately.

Fixed expressions like 諦あきらめるな, 心配しんぱいするな, and 忘わすれるな have crossed every gender and age boundary. They read as warm encouragement rather than commands because context does all the heavy lifting — proof that even the most forceful grammatical form can carry softness when the intent is right.

Related Grammar Points

• Imperative Form — Commanding and Ordering (Grammar N3)
• ことにしている — Make It A Rule To / I Always Make Sure To (Grammar N3)
• ざるを得ない — Have No Choice But (Grammar N3)
• わけにはいかない — Cannot Afford To (Grammar N3)
• Potential Form (可能形) — How to Express Ability (Grammar N3)
• Grammar Point: 気味 (gimi) — A Slight Tendency / Feeling A Bit Like (Grammar N3)

JLPT Tips

On the N3 examination, 禁止形 appears across multiple question types. Reading comprehension sections may place it in dialogue passages, narrative fiction, or reported speech. Instantly recognizing dictionary-form verb + な as a prohibition — not the sentence-final particle — is critical. Get that wrong and the tone, intent, and character relationships all shift.

In grammar selection questions, you may be asked to choose the correct prohibition form for a given context. Read the register of each scenario carefully. If the situation involves a teacher, a customer, a formal meeting, or any polite setting, 〜ないでください is almost certainly the intended answer. If it involves an emergency, a coach, a parent scolding a child, or a dramatic literary moment, 禁止形 may be what is being tested.

The trickiest part: distinguishing the two uses of sentence-final な. One rule covers it — if な follows a dictionary-form verb like 行いく、食たべる、or する, it is a prohibition. After an adjective（寒さむいな）, a past-tense verb（行いったな）, or a noun, it is the emotional/agreement particle. Drill it until it is automatic.

Know the hierarchy of prohibition strength — N3 tests it directly. 禁止形（〜な）is the bluntest; 〜ないで is casual and soft; 〜ないでください is politely direct; 〜てはいけない states a rule; 〜てはならない is the most formal written prohibition. Matching form to context matters as much as knowing the structure itself.

One last thing: know these fixed expressions cold, as they appear across both grammar questions and reading comprehension — 諦あきらめるな（Don't give up）、心配しんぱいするな（Don't worry）、忘わすれるな（Don't forget）、泣なくな（Don't cry）、負まけるな（Don't lose）. Spot them instantly, feel their emotional weight, and you will be ready for every N3 section.