The Collaborative International Dictionary of English v.0.48:

Befool \Be*fool"\, v. t. [imp. & p. p. Befooled; p. pr. & vb.
   n. Befooling.] [OE. befolen; pref. be- + fol fool.]
   1. To fool; to delude or lead into error; to infatuate; to
      deceive.
      [1913 Webster]

            This story . . . contrived to befool credulous men.
                                                  --Fuller.
      [1913 Webster]

   2. To cause to behave like a fool; to make foolish. "Some
      befooling drug." --G. Eliot.
      [1913 Webster]

WordNet (r) 3.0 (2006):

befool
    v 1: make a fool or dupe of [syn: fool, gull, befool]
    2: fool or hoax; "The immigrant was duped because he trusted
       everyone"; "You can't fool me!" [syn: gull, dupe,
       slang, befool, cod, fool, put on, take in, put
       one over, put one across]