5 · Expressions (level 5)
Not necessarily: wèibì, bújiànde and bù yídìng
softened negation
Three ways to doubt that something must be so — without saying that it is not.
A flat “no” is often too strong, in Chinese as in English. These three words deny the “must”, not the fact: 贵的东西不一定好 does not say that expensive things are bad, only that they are not bound to be good. All three stand where adverbs stand, before the verb or adjective.
不一定 is the neutral, everyday one. It also simply means “it is not certain”: 我明天不一定有空, “I may not be free tomorrow”. It works as a complete answer too: 不一定, “not necessarily, it depends”.
未必 sounds more considered and more doubtful, and it is common in writing and careful speech: 网上的评价未必可靠. 不见得 is the spoken, sceptical one — “I doubt it, I wouldn’t bet on it” — and often answers someone else’s claim: 我看不见得.
The order of 不 and 一定 decides everything. 不一定 is “not necessarily”; 一定不 is “definitely not”. The word that comes first is the one that governs the rest.
The form
| not necessarily (neutral) | 贵的东西不一定好。 |
| not necessarily (considered) | 他说的未必是真的。 |
| I doubt it (spoken) | 这样做不见得有用。 |
| as a short answer | 那也不一定。 |
| definitely not, for contrast | 他一定不会来。 |
The rules one by one
The form this topic is about
These words stand before the verb or adjective and deny that something must be so, not that it is so.
学历高的人不一定能力强。People with more qualifications are not necessarily more capable.
不一定 is neutral and also means “it is not certain”; it is the everyday choice.
我明天不一定有空。I may not be free tomorrow.
未必 sounds more considered and more doubtful, and is common in writing.
网上的评价未必可靠。Online reviews are not necessarily reliable.
不见得 is the spoken, sceptical version: “I wouldn’t bet on it”.
你觉得他会同意？我看不见得。You think he’ll agree? I doubt it.
一定不 means “definitely not”: the order of the two words decides the meaning.
你一定不要告诉他。You absolutely must not tell him.
A closer look
Disagreeing without contradicting
In Chinese conversation a direct “that’s wrong” can sound abrupt, especially to someone older or more senior. These words let a speaker disagree while leaving room: 也不一定吧, “not necessarily, surely?”, or 那也未必, “that isn’t necessarily so”. The softening 吧 and the small 也 make the doubt sound even more like an invitation to think again.
不见得 is the most pointed of the three. 那可不见得 is a confident “I wouldn’t be so sure about that” and can sound like a challenge. 未必 belongs to essays and discussions, and it can also form a double negative, 未必不, “not necessarily not” — a careful way of saying “quite possibly”.
How to spot it
- 不一定
- 未必
- 不见得
- 也未必
- 那可不见得
Example sentences
好看的电影不一定有很多人看。A good film doesn’t necessarily draw a big audience.
他今天不一定会来。He might not come today.
价格低未必就划算。A low price is not necessarily a good deal.
老办法未必不好。The old way is not necessarily a bad one.
他嘴上说得好听，心里不见得这么想。He says all the right things, but I doubt that’s what he really thinks.
多花钱不见得能解决问题。Spending more money won’t necessarily solve the problem.
7 more example sentences
名牌大学毕业的人未必都能找到好工作。Not every graduate of a famous university finds a good job.
这个消息不一定准确。This news is not necessarily accurate.
明天会不会下雨还不一定。It isn’t certain yet whether it will rain tomorrow.
他看起来很有钱，其实也未必。He looks rich, but that isn’t necessarily so.
你以为他不知道？那可不见得。You think he doesn’t know? I wouldn’t be so sure.
第一次见面的印象不一定对。First impressions are not necessarily right.
人多未必力量大。More people does not necessarily mean more strength.
Worth knowing (1)
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Bù yídìng for “not always”
About a habit or a timetable, 不一定 means “not always, not every time”. English uses a different word here, but the logic is the same: it is not certain that on any given occasion it will be so.
他周末不一定在家。He isn’t always at home at weekends.
The trap English speakers fall into
Watch out
English puts “not” first in “not necessarily”, and so does Chinese — but learners who think “necessarily not” in the back of their mind write 一定不, which says “expensive clothes are definitely no good”. The word that comes first governs what follows: 不 first to doubt the certainty.
Put bù before yídìng to doubt the “must”; wèibì and bújiànde doubt it more pointedly.
Your turn
8 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.