The Collaborative International Dictionary of English v.0.48:

Equivocation \E*quiv`o*ca"tion\, n.
   The use of expressions susceptible of a double signification,
   with a purpose to mislead.
   [1913 Webster]

         There being no room for equivocations, there is no need
         of distinctions.                         --Locke.

   Syn: Prevarication; ambiguity; shuffling; evasion; guibbling.
        See Equivocal, a., and Prevaricate, v. i.
        [1913 Webster]

WordNet (r) 3.0 (2006):

equivocation
    n 1: a statement that is not literally false but that cleverly
         avoids an unpleasant truth [syn: evasion, equivocation]
    2: intentionally vague or ambiguous [syn: equivocation,
       prevarication, evasiveness]
    3: falsification by means of vague or ambiguous language [syn:
       equivocation, tergiversation]