急に (きゅうに): 'Suddenly' / 'All of a Sudden'
The adverb for "no warning"
急に describes something happening suddenly, abruptly, or unexpectedly — without warning. It's an adverb, so it sits in front of the verb and tells you how the action happened:
急に雨が降ってきた。
きゅうに あめが ふって きた。
It suddenly started to rain.
急に + verb = the classic pattern.
ヤッタンは急に呼ばれた。
ヤッタンは きゅうに よばれた。
Yattan was suddenly called over.
モチが急に立ち止まった。
モチが きゅうに たちどまった。
Mochi suddenly stopped walking.
Something unexpected, with no lead-up.
The feeling is everyday and natural — it's the word you reach for when ordinary plans get interrupted or the weather turns on you.
Before a noun, it becomes 急な
急に is only half of the word. Its source is the な-adjective 急(きゅう)な, "sudden / urgent," so the ending you pick depends on what you're modifying:
| You want to modify… | Use | Example |
|---|---|---|
| a verb (an action) | 急に | 急に泣き出した (suddenly burst out crying) |
| a noun (a thing) | 急な | 急な変化 (a sudden change) |
This is just the regular な-adjective split: な-adjective + に → adverb, な-adjective + な → before a noun. 静か → 静かに / 静かな behaves the same way as 急 → 急に / 急な. Slip and write 急に変化 before a noun, or 急な降ってきた before a verb, and the ending is simply on the wrong side — swap it and you're fine.
See both endings at work — first 急に in front of verbs:
先生が急に話を止めた。
せんせいが きゅうに はなしを とめた。
The teacher suddenly stopped talking.
弟が急に泣き出した。
おとうとが きゅうに なきだした。
Yattan's little brother suddenly burst into tears.
弟 = Yattan's brother here.
…then 急な in front of nouns:
急な用事ができました。
きゅうな ようじが できました。
Some urgent business came up.
急な + noun. 用事 = errand / business.
気温の急な変化に気をつけて。
きおんの きゅうな へんかに きを つけて。
Watch out for sudden changes in temperature.
Sorting 急に from its look-alikes
Two other words crowd in on 急に, and only one of them is a true synonym.
突然 (とつぜん) also means "suddenly," and in many sentences the two swap freely. The gap is tone: 突然 is more dramatic and a touch literary — "all of a sudden," out of nowhere — and lives in writing and storytelling (突然、電気が消えた = "all of a sudden the lights went out"). 急に has a more everyday, conversational feel and is the safer default in daily speech. 突然 isn't wrong; it just sounds bigger, so in casual conversation 急に is usually the more natural pick.
急いで (いそいで) looks related but points the other way. It comes from the verb 急ぐ (いそぐ = "to hurry") and describes doing something fast: 急いで食べた ("I ate in a hurry"). 急に is about something happening unexpectedly, not quickly. 急に出かけた = "I went out suddenly (unplanned)"; 急いで出かけた = "I went out in a hurry (rushing)." Reach for 急いで when you mean speed and you'll never overwrite the "unplanned" meaning of 急に.
Hold onto this
- 急に = "suddenly / abruptly," an adverb placed before a verb: 急に雨が降ってきた.
- It comes from the な-adjective 急な = "sudden / urgent," used before a noun: 急な変化.
- Rule: 急に + verb, 急な + noun.
- 突然 also means "suddenly" but feels more dramatic; 急いで means "hurriedly" (from 急ぐ) — a different word.
Practice it
Choose 急に or 急な to complete each sentence.
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
＿＿＿雨が降り出した。
Frequently asked questions
What's the difference between 急に and 急な?
Same word, two forms. 急に is the adverb — use it before a verb (急に止まった = suddenly stopped). 急な is the な-adjective form — use it before a noun (急な変化 = a sudden change).
Is 急に the same as 突然?
Both mean 'suddenly' and often swap freely. 突然 is more dramatic and literary ('all of a sudden'), while 急に sounds more everyday. In casual speech, 急に is usually the more natural pick.
How is 急に different from 急いで?
急に means 'suddenly / unexpectedly' (from the adjective 急). 急いで means 'hurriedly / in a hurry' (from the verb 急ぐ). 急いで食べた = ate quickly; 急に食べ始めた = suddenly started eating.
Can 急に go before a noun?
No. Before a noun, switch to the adjective form 急な: 急な用事 (urgent business), 急な雨 (a sudden rain). Keep 急に for modifying verbs.
Where 急に fits
Once this clicks, go on to
- ふと · N3 — ふと is an adverb meaning 'suddenly' or 'by chance' — a thought, glance, or realization arises unbidden. Learn ふと思い出す/見る/気づく and how it differs from 急に.
More N4 grammar to explore
Keep going with related patterns at the same level:
- 〜やすい・〜にくい — Add やすい or にくい to a verb ます-stem to say something is easy or hard to do: 読みやすい (easy to read), 食べにくい (hard to eat). They become い-adjectives and conjugate.
- 〜おきに — 〜おきに marks a repeating interval with a gap in between: 1日おきに = every other day, 2メートルおきに = every 2 meters. Learn the 'gap' logic and how it differs from 〜ごとに.
- 〜しか〜ない — 〜しか always pairs with a negative verb to mean 'only / nothing but,' with a 'not enough' nuance: 百円しかない. Learn the formation, particle rules, and しか vs だけ.
- 〜ているところ — ところ marks a moment in time: 〜るところ = about to do, 〜ているところ = right in the middle of doing, 〜たところ = just finished. Learn all three phases with clear examples.
- 〜てみる — 〜てみる means to do something and see how it goes — to try it out. Learn the て-form + みる formation, how みる conjugates (てみた, てみよう), and how it differs from 〜たい.
- 〜てすみません — 〜てすみません attaches すみません to a verb's て-form to say 'sorry for (doing).' Learn the formation, the negative 〜なくてすみません, and polite 〜て申し訳ありません.