Mor*da"cious*ly

from The Collaborative International Dictionary of English v.0.48

Mordacious \Mor*da"cious\, a. [L. mordax, -acis, fr. mordere,
   morsum, to bite. See {Morsel}.]
   Biting; given to biting; hence, figuratively, sarcastic;
   severe; scathing. -- {Mor*da"cious*ly}, adv.
   [1913 Webster]