The Collaborative International Dictionary of English v.0.48:

Quean \Quean\, n. [Originally, a woman, AS. cwene; akin to OS.
   quena, OHG. quena, Icel. kona, Goth qin?, and AS. cw['e]n,
   also to Gr. ? woman, wife, Skr. gn[=a] goddess. Cf. Queen.]
   1. A woman; a young or unmarried woman; a girl. [Obs. or
      Scot.] --Chaucer.
      [1913 Webster]

   2. A low woman; a wench; a slut. "The dread of every scolding
      quean." --Gay.
      [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

QUEAN. A worthless woman a strumpet. The meaning of this word, which is now
seldom used, is said not to be well ascertained. 2 Roll. Ab. 296 Bac. Ab.
Stander, U 3.