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"

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "desperation":
   acedia, anguish, anxiety, anxiousness, apathy, cave of Trophonius,
   cave of despair, defeatism, dejection, depression, despair,
   desperateness, despondency, disconsolateness, discouragement,
   distress, foolhardiness, forlornness, gloom, heedlessness,
   hopelessness, impetuosity, imprudence, melancholy, misery, no exit,
   no way, no way out, pessimism, rashness, recklessness, sloth,
   sorrow, wretchedness