The Collaborative International Dictionary of English v.0.48:
certified \certified\ adj.
   1. endorsed authoritatively as having met certain
      requirements; guranteed; as, certified milk; certified
      mail; a certified check. Opposite of uncertified.
      [Narrower terms: certificated, credentialed, documented;
      guaranteed] See also certifiable.
      [WordNet 1.5]
   2. legally insane according to clinical criteria.
   Syn: certifiable.
        [WordNet 1.5 +PJC]
   3. holding appropriate documentation and officially on record
      as qualified to perform a specified function or practice a
      specified skill.
   Syn: qualified.
        [WordNet 1.5]