adj
certain
SUR-tuhn
adj
1
Completely confident that something is true.
"She was certain she had locked the door."
2
Sure to happen; inevitable.
"A recession now seems 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."
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
Word Forms
more certain comparative, certainer comparative, Certains plural, most certain superlative, certainest superlative
Study it as flashcards or scroll it in Flow — saved to your collection.
Test yourself on “certain”
A quick quiz — meaning, synonyms & usage
→
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").