Valid and Certain

adjective

• Well grounded in logic or truth or having legal force.
  • usage: "a valid inference"; "a valid argument"; "a valid contract"
• Still legally acceptable.
  • usage: "the license is still valid"

• (a.) Having sufficient strength or force; founded in truth; capable of being justified, defended or supported; not weak or defective; sound; good; efficacious; as, a valid argument; a valid objection.
• (a.) Having legal strength or force; executed with the proper formalities; incapable of being rightfully overthrown or set aside; as, a valid deed; a valid covenant; a valid instrument of any kind; a valid claim or title; a valid marriage.
• (a.) Strong; powerful; efficient.

Legally binding; authorized.

adjective

• Definite but not specified or identified.
  • usage: "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.
  • usage: "felt certain of success"; "was sure (or certain) she had seen it"; "was very sure in his beliefs"; "sure of her friends"
  • synonyms: sure
• Established beyond doubt or question; definitely known.
  • usage: "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"
• Certain to occur; destined or inevitable.
  • usage: "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"
  • synonyms: sure
• Established irrevocably.
  • usage: "his fate is sealed"
  • synonyms: sealed
• Reliable in operation or effect.
  • usage: "a quick and certain remedy"; "a sure way to distinguish the two"; "wood dust is a sure sign of termites"
  • synonyms: sure
• Exercising or taking care great enough to bring assurance.
  • usage: "be certain to disconnect the iron when you are through"; "be sure to lock the doors"
  • synonyms: sure

• (a.) Fixed or stated; regular; determinate.
• (a.) Unfailing; infallible.
• (a.) Determined; resolved; -- used with an infinitive.
• (adv.) Certainly.
• (n.) A certain number or quantity.
• (a.) Not to be doubted or denied; established as a fact.
• (a.) Not specifically named; indeterminate; indefinite; one or some; -- sometimes used independenty as a noun, and meaning certain persons.
• (a.) Actually existing; sure to happen; inevitable.
• (a.) Assured in mind; having no doubts; free from suspicions concerning.
• (n.) Certainty.