noun (n)

• joint operation or action(noun.act)

  Example:
  Their cooperation with us was essential for the success of our mission.
  

  Antonym:
  competition, contention, rivalry
  

  source: wordnet30
• the practice of cooperating(noun.act)

  Example:
  Economic cooperation.
  They agreed on a policy of cooperation.
  

  source: wordnet30