The Collaborative International Dictionary of English v.0.48:

Question \Ques"tion\, n. [F., fr. L. quaestio, fr. quaerere,
   quaesitum, to seek for, ask, inquire. See Quest, n.]
   1. The act of asking; interrogation; inquiry; as, to examine
      by question and answer.
      [1913 Webster]

   2. Discussion; debate; hence, objection; dispute; doubt; as,
      the story is true beyond question; he obeyed without
      question.
      [1913 Webster]

            There arose a question between some of John's
            disciples and the Jews about purifying. -- John iii.
                                                  25.
      [1913 Webster]

            It is to be to question, whether it be lawful for
            Christian princes to make an invasive war simply for
            the propagation of the faith.         -- Bacon.
      [1913 Webster]

   3. Examination with reference to a decisive result;
      investigation; specifically, a judicial or official
      investigation; also, examination under torture.
      --Blackstone.
      [1913 Webster]

            He that was in question for the robbery. Shak.
            The Scottish privy council had power to put state
            prisoners to the question.            --Macaulay.
      [1913 Webster]

   4. That which is asked; inquiry; interrogatory; query.
      [1913 Webster]

            But this question asked
            Puts me in doubt. Lives there who loves his pain ?
                                                  --Milton.
      [1913 Webster]

   5. Hence, a subject of investigation, examination, or debate;
      theme of inquiry; matter to be inquired into; as, a
      delicate or doubtful question.
      [1913 Webster]

   6. Talk; conversation; speech; speech. [Obs.] --Shak.
      [1913 Webster]

   In question, in debate; in the course of examination or
      discussion; as, the matter or point in question.

   Leading question. See under Leading.

   Out of question, unquestionably. "Out of question, 't is
      Maria's hand." --Shak.

   Out of the question. See under Out.

   Past question, beyond question; certainly; undoubtedly;
      unquestionably.

   Previous question, a question put to a parliamentary
      assembly upon the motion of a member, in order to
      ascertain whether it is the will of the body to vote at
      once, without further debate, on the subject under
      consideration.

   Note: The form of the question is: "Shall the main question
         be now put?" If the vote is in the affirmative, the
         matter before the body must be voted upon as it then
         stands, without further general debate or the
         submission of new amendments. In the House of
         Representatives of the United States, and generally in
         America, a negative decision operates to keep the
         business before the body as if the motion had not been
         made; but in the English Parliament, it operates to
         postpone consideration for the day, and until the
         subject may be again introduced. In American practice,
         the object of the motion is to hasten action, and it is
         made by a friend of the measure. In English practice,
         the object is to get rid of the subject for the time
         being, and the motion is made with a purpose of voting
         against it. --Cushing.

   To beg the question. See under Beg.

   To the question, to the point in dispute; to the real
      matter under debate.
      [1913 Webster]

   Syn: Point; topic; subject.
        [1913 Webster]

WordNet (r) 3.0 (2006):

in question
    adj 1: open to doubt or suspicion; "the candidate's doubtful
           past"; "he has a dubious record indeed"; "what one found
           uncertain the other found dubious or downright false";
           "it was more than dubitable whether the friend was as
           influential as she thought"- Karen Horney [syn:
           doubtful, dubious, dubitable, in question(p)]

Moby Thesaurus II by Grady Ward, 1.0:

62 Moby Thesaurus words for "in question":
   arguable, at issue, before the house, conditional, conditioned,
   confutable, conjectural, contestable, contingent, controversial,
   controvertible, debatable, deniable, dependent, depending,
   disputable, doubtable, doubtful, dubious, dubitable, iffy,
   in debate, in dispute, in doubt, in dubio, in suspense,
   in the balance, mistakable, moot, on the agenda, on the docket,
   on the floor, on the table, open, open for discussion,
   open to doubt, open to question, pendent, pending, problematic,
   questionable, refutable, speculative, sub judice, suppositional,
   suspect, suspenseful, suspicious, uncounted, undecided,
   under active consideration, under advisement, under consideration,
   under examination, under investigation, under surveillance,
   undetermined, unestablished, unfixed, unsettled, untold,
   up for grabs