noun (n)

• a message expressing an opinion based on incomplete evidence(noun.communication)

  Synonym:
  conjecture, guess, hypothesis, supposition, surmisal, surmise
  

  source: wordnet30
• a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence)(noun.cognition)

  Example:
  Speculations about the outcome of the election.
  

  Synonym:
  conjecture
  

  source: wordnet30
• an investment that is very risky but could yield great profits(noun.possession)

  Example:
  He knew the stock was a speculation when he bought it.
  

  Synonym:
  venture
  

  source: wordnet30
• continuous and profound contemplation or musing on a subject or series of subjects of a deep or abstruse nature(noun.cognition)

  Synonym:
  meditation
  

  source: wordnet30
• The act of speculating.(noun)

  source: webster1913