Source : Webster's Revised Unabridged Dictionary (1913)

Soil \Soil\, v. t. [imp. & p. p. {Soiled}; p. pr. & vb. n.
   {Soiling}.] [OF. saoler, saouler, to satiate, F. so[^u]ler,
   L. satullare, fr. satullus, dim. of satur sated. See
   {Satire}.]
   To feed, as cattle or horses, in the barn or an inclosure,
   with fresh grass or green food cut for them, instead of
   sending them out to pasture; hence (such food having the
   effect of purging them), to purge by feeding on green food;
   as, to soil a horse.

Source : WordNet®

soiled
     adj : soiled or likely to soil with dirt or grime; "dirty unswept
           sidewalks"; "a child in dirty overalls"; "dirty slums";
           "piles of dirty dishes"; "put his dirty feet on the
           clean sheet"; "wore an unclean shirt"; "mining is a
           dirty job"; "Cinderella did the dirty work while her
           sisters preened themselves" [syn: {dirty}, {unclean}]
           [ant: {clean}]