The Collaborative International Dictionary of English v.0.48:

Thwite \Thwite\, v. t. [AS. [thorn]w[imac]tan. See Whittle,
   and cf. Thwaite a piece of land.]
   To cut or clip with a knife; to whittle. [Obs. or Prov. Eng.]
   --Chaucer.
   [1913 Webster]