The Collaborative International Dictionary of English v.0.48:

Misinform \Mis`in*form"\, v. t.
   To give untrue information to; to inform wrongly.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Misinform \Mis`in*form"\, v. i.
   To give untrue information; (with against) to calumniate.
   [R.] --Bp. Montagu.
   [1913 Webster]

WordNet (r) 3.0 (2006):

misinform
    v 1: give false or misleading information to [syn: misinform,
         mislead]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "misinform":
   bowl a googly, con, corrupt, deceive, defraud, delude, dupe, fool,
   gull, lead astray, misadvise, misdirect, miseducate, misguide,
   misinstruct, mislead, misteach, mystify, obfuscate, obscure,
   pervert, throw a curve