Source : Webster's Revised Unabridged Dictionary (1913)

Sitfast \Sit"fast`\, a. [Sit + fast.]
   Fixed; stationary; immovable. [R.]

         'T is good, when you have crossed the sea and back, To
         find the sitfast acres where you left them. --Emerson.

Sitfast \Sit"fast`\, n. (Far.)
   A callosity with inflamed edges, on the back of a horse,
   under the saddle.