a. [ Sit + fast. ] Fixed; stationary; immovable. [ R. ] [ 1913 Webster ]

'T is good, when you have crossed the sea and back,
To find the sitfast acres where you left them. Emerson. [ 1913 Webster ]

n. (Far.) A callosity with inflamed edges, on the back of a horse, under the saddle. [ 1913 Webster ]