The Collaborative International Dictionary of English v.0.48:

Desperation \Des`per*a"tion\, n. [L. desperatio: cf. OF.
   desperation.]
   1. The act of despairing or becoming desperate; a giving up
      of hope.
      [1913 Webster]

            This desperation of success chills all our industry.
                                                  --Hammond.
      [1913 Webster]

   2. A state of despair, or utter hopeless; abandonment of
      hope; extreme recklessness; reckless fury.
      [1913 Webster]

            In the desperation of the moment, the officers even
            tried to cut their way through with their swords.
                                                  --W. Irving.
      [1913 Webster]

WordNet (r) 3.0 (2006):

desperation
    n 1: a state in which all hope is lost or absent; "in the depths
         of despair"; "they were rescued from despair at the last
         minute"; "courage born of desperation" [syn: despair,
         desperation]
    2: desperate recklessness; "it was a policy of desperation"