Source : Webster's Revised Unabridged Dictionary (1913)

Priapism \Pri"a*pism\, n. [L. priapismus, Gr. ?, from Priapus
   the god of procreation, the penis, Gr. ?: cf. F. priapisme.]
   (Med.)
   More or less permanent erection and rigidity of the penis,
   with or without sexual desire.

Source : WordNet®

priapism
     n : condition in which the penis is continually erect; usually
         painful and seldom with sexual arousal