The Collaborative International Dictionary of English v.0.48:

Fash \Fash\, v. t. [imp. & p. p. Fashed; p. pr. & vb. n.
   Fashing.] [OF. faschier, F. f?cher, to anger, vex; cf. Pr.
   fasticar, fastigar, fr. L. fastidium dilike. See
   Fastidious.]
   To vex; to tease; to trouble. [Scot.]
   [1913 Webster]