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 ships 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)
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)
(Science: medicine) a strike by the batsman when any part of his person is outside of the lines of his position. To fall foul, to fall out; to quarrel. If they be any ways offended, they fall foul. to fall, or run, foul of. See fall. To make foul water, to sail in such shallow water 5c8
Origin: oe. Foul, ful, as. Ful; akin to D. Vuil, g. Faul rotten, OHG. Ful, Icel. Ful foul, fetid; dan. Fuul, Sw. Ful foul, goth. Fuls fetid, lith. Puti to be putrid, L. Putere to stink, be putrid, pus pus, gr. Pyon pus, to cause to rot, Skr. Puy to stink. 82. Cf. Defile to foul, file to foul, filth, pus, putrid.