· definite but not specified or identified; "set aside a certain sum each week"; "to a certain degree"; "certain breeds do not make good pets"; "certain members have not paid their dues"; "a certain popular teacher"; "a certain Mrs. Jones"

· having or feeling no doubt or uncertainty; confident and assured; "felt certain of success"; "was sure (or certain) she had seen it"; "was very sure in his beliefs"; "sure of her friends"

Synonym(s): sure

Antonym(s): uncertain

· established beyond doubt or question; definitely known; "what is certain is that every effect must have a cause"; "it is certain that they were on the bus"; "his fate is certain"; "the date for the invasion is certain"

Antonym(s): uncertain

· certain to occur; destined or inevitable; "he was certain to fail"; "his fate is certain"; "In this life nothing is certain but death and taxes"- Benjamin Franklin; "he faced certain death"; "sudden but sure regret"; "he is sure to win"

Synonym(s): sure

Antonym(s): uncertain

· established irrevocably; "his fate is sealed"

Synonym(s): sealed

· reliable in operation or effect; "a quick and certain remedy"; "a sure way to distinguish the two"; "wood dust is a sure sign of termites"

Synonym(s): sure

· exercising or taking care great enough to bring assurance; "be certain to disconnect the iron when you are through"; "be sure to lock the doors"

Synonym(s): sure