The Collaborative International Dictionary of English v.0.48:

Snick \Snick\, n. & v. t.
   See Sneck. [Prov. Eng. & Scot.]
   [1913 Webster]

   Snick up, shut up; silenced. See Sneck up, under Sneck.
      [1913 Webster]

            Give him money, George, and let him go snick up.
                                                  --Beau. & Fl.
      [1913 Webster]