Source : Webster's Revised Unabridged Dictionary (1913)

Nympholepsy \Nym"pho*lep`sy\, n. [Gr. ? a nymph + ? to seize.]
   A species of demoniac enthusiasm or possession coming upon
   one who had accidentally looked upon a nymph; ecstasy. [R.]
   --De Quincey.

         The nympholepsy of some fond despair.    --Byron.

Source : WordNet®

nympholepsy
     n : a frenzy of emotion; as for something unattainable