The Collaborative International Dictionary of English v.0.48:

Knobstick \Knob"stick`\, n.
   1. One who refuses to join, or withdraws from, a trade union.
      [Cant, Eng.]
      [1913 Webster]

   2. A stick, cane, or club terminating in a knob; esp., such a
      stick or club used as a weapon or missile; a knobkerrie.
      [Webster 1913 Suppl.]