The Collaborative International Dictionary of English v.0.48:

Gleet \Gleet\, n. [OE. glette, glet, glat, mucus, pus, filth,
   OF. glete.] (Med.)
   A transparent mucous discharge from the membrane of the
   urethra, commonly an effect of gonorrhea. --Hoblyn.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gleet \Gleet\, v. i.
   1. To flow in a thin, limpid humor; to ooze, as gleet.
      --Wiseman.
      [1913 Webster]

   2. To flow slowly, as water. --Cheyne.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gleet
    n 1: a thin morbid discharge as from a wound or especially
         chronic gonorrhea

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "gleet":
   chyle, colostrum, discharge, festering, humor, ichor, lachryma,
   lactation, leukorrhea, lymph, matter, mattering, milk, mucor,
   mucus, peccant humor, phlegm, purulence, pus, rankling, rheum,
   running, saliva, sanies, serous fluid, serum, snot, suppuration,
   sweat, tear, teardrop, the whites, urine