verb (v)

• arrange or order by classes or categories(verb.cognition)

  Example:
  How would you classify these pottery shards--are they prehistoric?.
  

  Synonym:
  assort, class, separate, sort, sort out
  

  source: wordnet30
• declare unavailable, as for security reasons(verb.social)

  Example:
  Classify these documents.
  

  Antonym:
  declassify
  

  source: wordnet30
• assign to a class or kind(verb.cognition)

  Synonym:
  relegate
  

  source: wordnet30
• To distribute into classes; to arrange according to a system; to arrange in sets according to some method founded on common properties or characters.(verb)

  source: webster1913