The Collaborative International Dictionary of English v.0.48:

Befoul \Be*foul"\, v. t. [imp. & p. p. Befouled; p. pr. & vb.
   n. Befouling.] [Cf. AS. bef?lan; pref. be- + f?lan to foul.
   See Foul, a.]
   1. To make foul; to soil.
      [1913 Webster]

   2. To entangle or run against so as to impede motion.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

befouled \befouled\ adj.
   made disgustingly dirty. a building befouled with soot
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

befouled
    adj 1: made dirty or foul; "a building befouled with soot";
           "breathing air fouled and darkened with factory soot"
           [syn: befouled, fouled]