Drossiest

from The Collaborative International Dictionary of English v.0.48

Drossy \Dross"y\, a. [Compar. {Drossier}; superl. {Drossiest}.]
   Of, pertaining to, resembling, dross; full of dross; impure;
   worthless. " Drossy gold." --Dryden. "Drossy rhymes."
   --Donne. -- {Dross"i*ness}, n.
   [1913 Webster]