adjective
not used before a noun [more ~; most ~] :not having any doubt about something :convinced or sure
used with it to say that something is known to be true or correct
used to say that something will definitely happen or that someone will definitely do something
always used before a noun - used to refer to something or someone that is not named specifically
a certain
used to refer to a quality that is noticed but that is difficult to explain or describe
formal - used with the name of a person you do not know
for certain
without a doubt :definitely or certainly
make certain
to do something or find out something so that you have no doubt about whether something is true, correct, will happen, etc.
pronoun
formal :certain ones :particular members of a group :some
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