Tra từ certain - Từ điển Oxford Advanced Learner 8th

cer·tain adjective, pronoun BrE [ˈsɜːtn] NAmE [ˈsɜːrtn]
adjective
1. that you can rely on to happen or to be true
• The climbers face certain death if the rescue today is unsuccessful.
•~ (that)… It is certain that they will agree.
•~ to do sth She looks certain to win an Oscar.
•They are certain to agree.
•~ of sth/of doing sth If you want to be certain of getting a ticket, book now.
2. firmly believing sth; having no doubts
•~ (that)… She wasn't certain (that) he had seen her.
•~ of/about sth Are you absolutely certain about this?
•~ who/where, etc… I'm not certain who was there.
•To my certain knowledge he was somewhere else at the time (= I am sure about it).
3. used to mention a particular thing, person or group without giving any more details about it or them
• For certain personal reasons I shall not be able to attend.
• Certain people might disagree with this.
•They refused to release their hostages unless certain conditions were met.
4. (formal)used with a person's name to show that the speaker does not know the person
•It was a certain Dr Davis who performed the operation.
5. slight; noticeable, but difficult to describe
• That's true, to a certain extent.
• I felt there was a certain coldness in her manner.

Word Origin:
Middle English: from Old French, based on Latin certus ‘settled, sure’.

Thesaurus:
certain adj.
1.
•She looks certain to win an Oscar.
bound • • sure • • guaranteed • • conclusive • • undeniable • • indisputable • • unquestionable • |formal destined • |written assured • |especially spoken definite •
Opp: uncertain
certain/sure/assured of sth
certain/bound/sure/guaranteed/destined to do sth
certain/conclusive/undeniable/indisputable/unquestionable/definite that…
2.
•Are you certain about this?
sure • • confident • • convinced • • clear • • satisfied • |especially spoken positive •
Opp: uncertain
certain/sure/confident/convinced/clear/positive about sth
certain/sure/confident/convinced/satisfied of sth
certain/sure/confident/convinced/clear/satisfied/positive that…
certain/sure/clear/satisfied who/what/how…
Certain or sure? Certain is slightly more formal and less frequent than sure. Both words are often used in negative statements and questions.
3.
•Certain people might disagree.
particular • • specific •
a certain/particular/specific event/incident/occasion/date
certain/particular/specific needs/requirements
a certain/particular/specific type/kind of sth

Synonyms:
certain
bound • sure • definite • guaranteed
These are all words describing sth that will definitely happen or is definitely true.
certain • that you can rely on to happen or be true: ▪ It's certain that they will agree. ◇ ▪ They are certain to agree.
bound • [not before noun] certain to happen, or to do or be sth. Bound is only used in the phrase bound to do/be, etc.: ▪ There are bound to be changes when the new system is introduced. ◇ ▪ You've done so much work— you're bound to pass the exam.
sure • certain to happen or be true; that can be trusted on relied on: ▪ She's sure to be picked for the team. ◇ ▪ It's sure to rain.
definite • (rather informal) certain to happen; that is not going to change: ▪ Is it definite that he's leaving?
guaranteed • certain to have a particular result: ▪ That kind of behaviour is guaranteed to make him angry.
certain/sure of sth
certain/bound/sure/guaranteed to do sth
certain/definite that…
I couldn't say for certain/sure/definite.

Synonyms:
sure
confident • convinced • certain • positive • clear
These words all describe sb who knows without doubt that sth is true or will happen.
sure • [not before noun] without any doubt that you are right, that sth is true, that you will get sth or that sth will happen: ▪ ‘Is that John over there?’ ‘I'm not sure.’ ◇ ▪ Are you sure about that? ◇ ▪ England must win this game to be sure of qualifying.
Sure is often used in negative statements and questions, because there is some doubt or anxiety over the matter. If there is no doubt, people often say quite sure: ▪ I'm quite sure (that) I left my bag here ▪ (= I have no doubt about it) ▪.
confident • completely sure that sth will happen in the way that you want or expect: ▪ I'm quite confident that you'll get the job. ◇ ▪ The team feels confident of winning.
Confident is a stronger and more definite word than sure and is more often used in positive statements, when you feel no anxiety.
convinced • [not before noun] completely sure that sth is true or right, especially because the evidence seems to prove it or sb else has persuaded you to believe it: ▪ I'm convinced that she's innocent.
certain • [not usually before noun] sure that you are right or that sth is true: ▪ Are you absolutely certain about this?
sure or certain?
Like sure, certain is often used in negative statements and questions. It is slightly more formal than sure; sure is more frequent, especially in spoken English.
positive • [not before noun] (rather informal) completely sure that sth is true: ▪ She was positive that he'd been there. ◇ ▪ ‘Are you sure?’ ‘Positive.’
clear • (often used in negative statements and questions) having no doubt or confusion about sth: ▪ My memory isn't really clear on that point.
sure/confident/convinced/certain/positive/clear about sth
sure/confident/convinced/certain of sth
sure/confident/convinced/certain/positive/clear that…
sure/certain/clear who/what/how, etc.
to feel sure/confident/convinced/certain/positive
quite/absolutely/completely/fairly/pretty sure/confident/convinced/certain/positive/clear
not altogether sure/confident/convinced/certain/clear

Example Bank:
•Digby looked certain to be the next president.
•I don't know for certain how many people are coming.
•I grew more and more certain that she was lying to me.
•I think she's a teacher, but I couldn't say for certain.
•It's by no means certain that she'll get the job.
•Make certain that you lock the door if you go out.
•He wasn't certain who he'd given the papers to.
•I couldn't say for certain whether she'll be there.
•If you want to be certain of getting into the concert, buy your ticket now.
•It's certain that they will agree.
•She wasn't certain (that) he'd seen her.
•The climbers face certain death if the rescue attempt is unsuccessful.
•They are certain to agree.
•To my certain knowledge he was somewhere else at the time.
•You have to be quite certain of the facts before making a decision.
Idioms: ↑for certain ▪ ↑make certain ▪ ↑make certain of of doing something ▪ ↑of a certain age

pronoun certain of… (formal)used for talking about some members of a group of people or things without giving their names
• Certain of those present were unwilling to discuss the matter further.

Word Origin:
[certain] Middle English: from Old French, based on Latin certus ‘settled, sure’.