The Collaborative International Dictionary of English v.0.48:

Overrule \O`ver*rule"\, v. t. [imp. & p. p. Overruled; p. pr.
   & vb. n. Overruling.]
   1. To rule over; to govern or determine by superior
      authority.
      [1913 Webster]

   2. To rule or determine in a contrary way; to decide against;
      to abrogate or alter; as, God overrules the purposes of
      men; the chairman overruled the point of order.
      [1913 Webster]

            His passion and animosity overruled his conscience.
                                                  --Clarendon.
      [1913 Webster]

            These [difficulties] I had habitually overruled.
                                                  --F. W.
                                                  Newman.
      [1913 Webster]

   3. (Law) To supersede, reject, annul, or rule against; as,
      the plea, or the decision, was overruled by the court.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Overrule \O`ver*rule"\, v. i.
   To be superior or supreme in rulling or controlling; as, God
   rules and overrules. --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

overrule
    v 1: rule against; "The Republicans were overruled when the
         House voted on the bill" [syn: overrule, overturn,
         override, overthrow, reverse]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "overrule":
   abolish, abrogate, annul, bear reign, cancel, countermand,
   counterorder, disannul, do away with, invalidate, make void,
   nullify, override, recall, recant, reign, renege, repeal, rescind,
   retract, reverse, revoke, rule, rule over, set aside, suspend,
   sway, vacate, void, waive, wear the crown, wield the scepter,
   withdraw, write off