The Collaborative International Dictionary of English v.0.48:

Prosaic \Pro*sa"ic\, Prosaical \Pro*sa"ic*al\, a. [L. prosaius,
   from prosa prose: cf. F,. prosa["i]que. See Prose.]
   1. Of or pertaining to prose; resembling prose; in the form
      of prose; unpoetical; writing or using prose; as, a
      prosaic composition. --Cudworth.
      [1913 Webster]

   2. Dull; uninteresting; commonplace; unimaginative; prosy;
      as, a prosaic person. --Ed. Rev.
      [1913 Webster] -- Pro*sa"ic*al*ly, adv. --
      Pro*sa"ic*al*ness, n.
      [1913 Webster]