noun (n)

• a religious orientation of doubt; a denial of ultimate knowledge of the existence of God(noun.cognition)

  Example:
  Agnosticism holds that you can neither prove nor disprove God's existence.
  

  source: wordnet30
• the disbelief in any claims of ultimate knowledge(noun.cognition)

  Synonym:
  scepticism, skepticism
  

  source: wordnet30
• That doctrine which, professing ignorance, neither asserts nor denies.(noun)

  source: webster1913