certain
SUR-tuhn
Certain (adj) means Completely confident that something is true. Example: “She was certain she had locked the door.”
adj
1
Completely confident that something is true.
"She was certain she had locked the door."
"I'm certain that I saw him leave the office before lunch."
"Are you certain this is the right address for the party?"
2
Sure to happen; inevitable.
"A recession now seems almost certain."
"With so many dark clouds overhead, rain this afternoon is certain."
"If you never practise, failure is almost certain."
det
1
Used to refer to a specific but unnamed person or thing.
"Certain foods can trigger an allergic reaction."
"A certain someone told me you got the job."
"There are certain rules you must follow when you visit the museum."
How to use certain
Learner’s notesIn plain EnglishSure or definite — either about a belief, an outcome, or referring to something specific but unspecified.
Common pairings
a certain amount
make certain
for certain
certain to happen
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Word forms
- Comparative
- more certain, certainer
- Superlative
- most certain, certainest
Fill the gap
Can you complete this real example?
She was _____ she had locked the door.
Etymology
From Old French certain, from a Latin root related to certus ("fixed, settled, sure").
Synonyms
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Related words
Rhymes for certain
See all rhymes for certain →Frequently asked questions
What does “certain” mean?
The word “certain” means completely confident that something is true. In plain terms, sure or definite — either about a belief, an outcome, or referring to something specific but unspecified.
How do you pronounce “certain”?
“Certain” is pronounced SUR-tuhn (/ˈsɝ.tən/ in IPA).
How do you use “certain” in a sentence?
Here is “certain” used in a sentence: “She was certain she had locked the door.”
What is another word for “certain”?
Words with a similar meaning to “certain” include assured, clear, confident, doubtless, definite and positive.
What is the opposite of “certain”?
The opposite of “certain” — its antonyms — are uncertain, impossible, incidental and particular specific.
What part of speech is “certain”?
Depending on how it is used, “certain” can be an adjective and a det.
Where does the word “certain” come from?
The word “certain” comes from Latin. From Old French certain, from a Latin root related to certus ("fixed, settled, sure").
Is “certain” a common word?
“Certain” is a very common word in modern English, usually learned at around the A2 level.
What is the difference between certain and sure?
The two are very close, and often interchangeable — both mean confident that something is true. 'Certain' tends to sound a little more formal and absolute, suggesting no room for doubt at all. 'Sure' is more casual and everyday. You might feel sure of an answer, but certain of a proven fact.
What is the opposite of certain?
The main opposites are uncertain, unsure, and doubtful — words describing a lack of confidence that something is true. If you are certain, you have no doubt; if you are uncertain, you are still weighing the possibilities. 'Doubtful' and 'in two minds' capture that same feeling of not yet being convinced.
Does 'certain' have more than one meaning?
Yes. Besides meaning fully confident, 'certain' can point to something particular but unnamed, as in 'a certain person called' or 'under certain conditions.' Here it hints at a specific thing without spelling it out. The same word can also mean guaranteed to happen, as in 'certain victory.' Context makes clear which sense applies.
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