Source : Webster's Revised Unabridged Dictionary (1913)

Foul \Foul\ (foul), a. [Compar. Fouler (-[~e]r); superl.
   {Foulest}.] [OE. foul, ful, AS. f[=u]l; akin to D. vuil, G.
   faul rotten, OHG. f[=u]l, Icel. f[=u]l foul, fetid; Dan.
   fuul, Sw. ful foul, Goth. f[=u]ls fetid, Lith. puti to be
   putrid, L. putere to stink, be putrid, pus pus, Gr. py`on
   pus, to cause to rot, Skr. p[=u]y to stink. [root]82. Cf.
   {Defile} to foul, {File} to foul, {Filth}, {Pus}, {Putrid}.]
   1. Covered with, or containing, extraneous matter which is
      injurious, noxious, offensive, or obstructive; filthy;
      dirty; not clean; polluted; nasty; defiled; as, a foul
      cloth; foul hands; a foul chimney; foul air; a ship's
      bottom is foul when overgrown with barnacles; a gun
      becomes foul from repeated firing; a well is foul with
      polluted water.

            My face is foul with weeping.         --Job. xvi.
                                                  16.

   2. Scurrilous; obscene or profane; abusive; as, foul words;
      foul language.

   3. Hateful; detestable; shameful; odious; wretched. ``The
      foul with Sycorax.'' --Shak.

            Who first seduced them to that foul revolt?
                                                  --Milton.

   4. Loathsome; disgusting; as, a foul disease.

   5. Ugly; homely; poor. [Obs.] --Chaucer.

            Let us, like merchants, show our foulest wares.
                                                  --Shak.

   6. Not favorable; unpropitious; not fair or advantageous; as,
      a foul wind; a foul road; cloudy or rainy; stormy; not
      fair; -- said of the weather, sky, etc.

            So foul a sky clears not without a storm. --Shak.

   7. Not conformed to the established rules and customs of a
      game, conflict, test, etc.; unfair; dishonest;
      dishonorable; cheating; as, foul play.

   8. Having freedom of motion interfered with by collision or
      entanglement; entangled; -- opposed to clear; as, a rope
      or cable may get foul while paying it out.