dirk knife

from The Collaborative International Dictionary of English v.0.48

Dirk \Dirk\, n. [Ir. duirc.]
   A kind of dagger or poniard; -- formerly much used by the
   Scottish Highlander.
   [1913 Webster]

   {Dirk knife}, a clasp knife having a large, dirklike blade.
      [1913 Webster]