Plain Negative 〜ない

The plain negative — the 〜ない form — is how you say don't and won't casually: with friends, with family, in a diary, or in your own head. It is the negative partner of the dictionary form, and the casual counterpart of the polite 〜ません. This page covers what it means and what it looks like across the verb classes; the step-by-step machinery lives on forming 〜ない.

Two ideas make this form easy to trust once you have them:

1. 〜ない replaces the whole affirmative ending — you don't add a "not" word next to the verb, you swap the verb's tail.
2. 〜ない then behaves like an い-adjective — it is not frozen. It has a past (食べなかった), a te-form (食べなくて), and a polite form (食べないです), all following adjective rules.

What it looks like across the classes

Here is the shape of the form for one verb from each class. The negative always ends in ない; what changes is how you reach the stem it attaches to.

Notice that 〜ない, like the dictionary form, is tenseless about the future/present split — 行かない is both I don't go (habit) and I'm not going (this specific plan), just as English I'm not going can mean either.

The one class that hides a わ: vowel-final う-verbs

For most godan verbs, the negative stem is the あ-row of the verb's consonant column (書かない, 飲まない, 話さない). But godan verbs whose dictionary form ends in a bare う — 買う, 会う, 使う, 言う — do something the kana chart hides. They do not take あ. They insert わ:

This わ is a fossil. These verbs used to end in a /w/ sound (an old kawu), and that /w/ has vanished everywhere in the modern language except right before ない (and a few other あ-row endings). So the negative is the one place learners must actively remember the わ — it is the single most common slip on this whole form. There is no shortcut: when a godan verb ends in う, its negative reaches for わ.

〜ない is an adjective, not a fixed particle

Here is the fact that turns 〜ない from a memorized ending into a system you can extend. 〜ない conjugates exactly like the い-adjective 高い（たかい）. It ends in い, and everything that い-adjectives do, ない does:

This is why the past negative is 食べなかった and never ×食べないだった — ない is an adjective, so it takes かった like every other い-adjective, not the copula past だった. This single insight, worked out in full on 〜ない inflects like an い-adjective, unifies past-negatives, negative te-forms, and "not very" (あまり…ない) under rules you already know from adjectives.

Register: this is the casual form

The plain negative is casual register. Use it with people you are close to and inside subordinate clauses (行かないなら, 食べないとき), because the plain form is the default anywhere that isn't the final polite verb of a sentence. To end a sentence politely with a stranger, a customer, or a superior, switch to 〜ません.

Casual invitations: 〜ない？

Here is a bonus that mirrors the polite side of the language. Just as the polite 〜ませんか turns a negative into a friendly invitation, the plain 〜ない with a rising, questioning intonation is the casual version. 行かない？ said with an upturn does not mean aren't you going? — it means wanna go? The negative leaves the listener room to say no, which is exactly what makes it feel like an easygoing offer rather than pressure.

The clue that separates a real negative (行かない, I'm not going) from an invitation (行かない？, wanna go?) is the melody: a flat or falling tone states a fact, a clear rise makes it an offer. Context and the rising pitch do all the work — the words are identical.

Common mistakes

Key takeaways

• 〜ない replaces the affirmative ending; it is the casual don't / won't.
• Ichidan: drop る, add ない (食べない). Irregular: しない, 来ない（こない）.
• Godan uses the あ-row — but bare-う verbs insert わ: 買う → 買わない, never ×買あない.
• 〜ない then inflects like the い-adjective 高い: past 食べなかった, te-form 食べなくて.
• It is casual; the polite equivalent is 〜ません.