What is "fitchew"

Foumart \Fou"mart`\, n. [OE. folmard, fulmard; AS. f[=u]l foul + mear[eth], meard, marten: cf. F. marte, martre. See Foul, a., and Marten the quadruped.] (Zo["o]l.) The European polecat; -- called also European ferret, and fitchew. See Polecat. [Written also foulmart, foulimart, and fulimart.]

n. (context obsolete English) polecat