supernaculum

Supernaculum \Su`per*nac"u*lum\, adv. & n. [NL., from L. super
   over + G. nagel, a nail, as of the finger, or a corruption of
   L. super and ungulam claw.]
   1. A kind of mock Latin term intended to mean, upon the nail;
      -- used formerly by topers. --Nares.
      [1913 Webster]

            Drinking super nagulum [supernaculum], a device of
            drinking, new come out of France, which is, after a
            man hath turned up the bottom of the cup, to drop it
            on his nail and make a pearl with that is left;
            which if it slide, and he can not make it stand on
            by reason there is too much, he must drink again for
            his penance.                          --Nash.
      [1913 Webster]

   2. Good liquor, of which not enough is left to wet one's
      nail. --Grose.
      [1913 Webster]