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HSK 3

一定

certain; definitely

adverbneutral2 episodes
一
yī1st tone
定
dìng4th tone

HSK level

1
2
3
4
5
6
Pinyin
yídìng
Part of speech
adverb
Level
HSK 3
Strokes
9
Register
neutral
In episodes
2

Stroke order for 一定

一定 is written with 9 strokes (一: 1, 定: 8). The animation replays automatically.

What does 一定 mean?

一定 (yídìng) is a high-frequency adverb meaning 'definitely, certainly, for sure' — used to express strong certainty about what is, was, or will be true.

It can also function as an adjective meaning 'a certain (amount of), a definite' (一定的经验 'a certain amount of experience'). Two things English speakers often miss. First, 一定 expresses the speaker's confidence, not external proof — 他一定来 means 'he will definitely come (I'm sure)', not 'it has been confirmed he will come'.

Second, in promises and commitments 一定 is the standard way to make a vow: 我一定来 ('I'll definitely be there'), 我一定记得 ('I'll be sure to remember'). The negative form is 不一定 ('not necessarily'), which is itself one of the most useful expressions in spoken Chinese. Note the tone change: 一 is yì by default but becomes yí before a fourth tone (dìng).

Character by character

一yīone; fixed
+
定dìngto set; fixed; certain
=
一定

Memory hook: 一 (one, fixed) + 定 (settled) = one settled answer = definitely.

Hear 一定 in real episodes

一定 appears in 2 Fluentide podcast episodes at natural native speed — each with the full Chinese script, pinyin, and line-by-line English translation.

Wikipedia Was Wrong for 41 Minutes, So Google Said Altman Was Dead一定 spoken at natural speedeasyStar Wars' New Anime "The Ninth Jedi" Is Out, Redrawn From Scratch by a Japanese Studio一定 spoken at natural speedeasy
Browse the full episode library

Example sentences

我一定来。

Wǒ yídìng lái.

I'll definitely come.

spoken

你一定要小心。

Nǐ yídìng yào xiǎoxīn.

You absolutely must be careful.

spoken

他不一定知道。

Tā bù yídìng zhīdào.

He doesn't necessarily know.

neutral

明天一定会下雨。

Míngtiān yídìng huì xià yǔ.

It will definitely rain tomorrow.

neutral

这件事我们一定要做好。

Zhè jiàn shì wǒmen yídìng yào zuò hǎo.

We must do this thing well, no matter what.

neutral, written

Common phrases with 一定

一定要yídìng yàomust / definitely have to
不一定bù yídìngnot necessarily
一定会yídìng huìwill definitely (do)
一定是yídìng shìmust be / is definitely
说不定shuō bu dìngmaybe; can't say for sure

Synonyms

肯定kěndìng

肯定 also means 'definitely, certainly' and is largely interchangeable with 一定 as an adverb of certainty. 肯定 sounds slightly more spoken-emphatic ('I'm positive'), while 一定 is more neutral and is the preferred choice in promises (我一定到, 'I'll definitely be there').

必须bìxū

必须 means 'must / have to' (obligation). 一定要 means 'must / definitely have to' but feels more personal and less rigid. Rules and laws use 必须; personal resolve uses 一定要.

Don't confuse 一定 with

一直yìzhí

一直 means 'continuously / all along' (a temporal adverb). 一定 means 'definitely' (a certainty adverb). Same first character, different meanings: 一直在 ('have been there all along') vs 一定在 ('must definitely be there').

决定juédìng

决定 means 'to decide' (verb) or 'decision' (noun). 一定 is an adverb of certainty. 我决定了 ('I've decided') vs 我一定来 ('I will definitely come').

规定guīdìng

规定 means 'rule / regulation' or 'to stipulate'. 一定 means 'definitely'. They share the character 定 ('fixed') but function very differently.

FAQ

Related words from the same episodes

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