決して〜ない: 'Never' / 'By No Means'

Resolve or denial — the two feelings it carries

決して is an adverb that intensifies a negative. On its own it doesn't mean much; it leans forward and waits for the negative ending to land, then drives it home. The result is the English "never," "by no means," "absolutely not," or "on no account." It carries two closely related feelings: a firm resolve — a promise to yourself or someone else (決してあきらめない, "I will never give up") — and a strong denial that knocks an idea down flatly (決して簡単ではない, "it's by no means easy").

The negative ending is non-negotiable

決して sits before the predicate, and that predicate must end in a negative form — a verb, an い-adjective, or a な-adjective/noun.

The one rule that matters: no negative, no 決して. This is the mistake to guard against — 決して needs a negative, so say 決して忘れない ("I'll never forget"), never ✗決して忘れる. If your sentence ends affirmatively, 決して simply cannot be there. The negative works just as happily inside a relative clause or in the past tense:

決して vs 全然, 絶対, and めったに

Several adverbs cluster around negatives, but each measures a different thing — swap them and the meaning warps, not just the intensity:

• 決して〜ない = never, by no means — a categorical, 0% denial or firm resolve. It's about certainty and determination, not counting: 決して行かない ("I will never go").
• めったに〜ない = rarely, hardly ever — a statement about frequency. It's not zero; it just doesn't happen often: めったに行かない ("I hardly ever go"). So "I rarely eat meat" is めったに食べない, never 決して食べない (which would be a vow, "I will never eat meat").
• 全然〜ない = not at all — emphatic degree, often about a current state or amount: 全然おもしろくない ("not interesting at all"). See 〜全然. For "it's not interesting at all," reach for 全然, not 決して.

Register sets 決して apart too. It's somewhat formal and emphatic — at home in earnest promises, warnings, and official notices ("決して立ち入らないでください," "on no account enter"). In casual chat you'd more often hear the everyday cousin 絶対 (ぜったい): 絶対あきらめない. Because 決して voices a categorical "never," it pairs naturally with strong statements of principle or prohibition — don't sprinkle it into light remarks where 絶対 or a plain negative fits better, or it sounds overly dramatic.

When the "no" hides at the end

The trickiest 決して sentences bury the negative far downstream, most famously in the 〜とは言えない ("cannot be called") frame. The adverb still points at that final negation, even when a whole clause sits between them:

On an exam, this is where a trap lurks: 決して安全だとは言えない looks like it praises safety until the 言えない at the very end flips it. Read to the end of the clause before deciding whether 決して is satisfied.

The short version

• 決して = never / by no means / absolutely not — always with a negative predicate.
• Two flavors: firm resolve (決してあきらめない) and strong denial (決して簡単ではない).
• No negative ending = ungrammatical; that's the #1 mistake.
• Register is formal/emphatic; casual speech often uses 絶対.
• Contrast: めったに〜ない = rarely (frequency); 全然〜ない = not at all (degree).

Practice it