The difference between Certain and Sure

When used as adjectives, certain means sure, positive, not doubting, whereas sure means physically secure and certain, non-failing, reliable.


Certain is also determiner with the meaning: having been determined but not specified.

Certain is also noun with the meaning: something certain.

Certain is also pronoun with the meaning: unnamed or undescribed members (of).

Sure is also interjection with the meaning: yes.

Sure is also adverb with the meaning: without doubt, certainly.

check bellow for the other definitions of Certain and Sure

  1. Certain as an adjective:

    Sure, positive, not doubting.

    Examples:

    "I was certain of my decision."

  2. Certain as an adjective (obsolete):

    Determined; resolved.

  3. Certain as an adjective:

    Not to be doubted or denied; established as a fact.

  4. Certain as an adjective:

    Actually existing; sure to happen; inevitable.

    Examples:

    "Bankruptcy is the certain outcome of your constant gambling and lending."

  5. Certain as an adjective:

    Unfailing; infallible.

  6. Certain as an adjective:

    Fixed or stated; regular; determinate.

  7. Certain as an adjective:

    Not specifically named; indeterminate; indefinite; one or some; sometimes used independently as a noun, and meaning certain persons; see also "one".

  1. Certain as a pronoun (with ''of''):

    Unnamed or undescribed members (of).

    Examples:

    "There where serious objections to certain of the proposals."

  1. Certain as a noun (with "the"):

    Something certain.

  1. Sure as an adjective:

    Physically secure and certain, non-failing, reliable.

    Examples:

    "This investment is a sure thing. The bailiff had a sure grip on the prisoner's arm."

  2. Sure as an adjective:

    Certain in one's knowledge or belief.

    Examples:

    "He was sure she was lying. I am sure of my eventual death. John was acting sure of himself but in truth had doubts."

  3. Sure as an adjective:

    Certain to act or be a specified way.

    Examples:

    "Be sure to lock the door when you leave."

  4. Sure as an adjective (obsolete):

    Free from danger; safe; secure.

  5. Sure as an adjective (obsolete):

    Betrothed; engaged to marry.

  1. Sure as an adverb (modal adverb):

    Without doubt, certainly.

    Examples:

    "Sure he's coming! Why wouldn't he?"

    "Did you kill that bear yourself? ―"I sure did!"