The Collaborative International Dictionary of English v.0.48:

Indifferently \In*dif"fer*ent*ly\, adv.
   In an indifferent manner; without distinction or preference;
   impartially; without concern, wish, affection, or aversion;
   tolerably; passably.
   [1913 Webster]

         That they may truly and indifferently minister justice,
         to the punishment of wickedness and vice, and to the
         maintenance of thy true religion, and virtue. --Book of
                                                  Com. Prayer
                                                  [Eng. Ed.]
   [1913 Webster]

         Set honor in one eye and death i' the other,
         And I will look on both indifferently.   --Shak.
   [1913 Webster]

         I hope it may indifferently entertain your lordship at
         an unbending hour.                       --Rowe.
   [1913 Webster]

WordNet (r) 3.0 (2006):

indifferently
    adv 1: with indifference; in an indifferent manner; "she
           shrugged indifferently"

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "indifferently":
   ad eundem, apathetically, as, as well, ceteris paribus, coldly,
   coolly, correspondingly, disinterestedly, dully, equally,
   equivalently, evenly, fair to middling, fairishly, fairly,
   halfheartedly, heartlessly, identically, impassively, listlessly,
   lukewarmly, mediocrely, middling well, middlingly, moderately,
   modestly, numbly, passably, perfunctorily, phlegmatically,
   plucklessly, proportionately, so, so-so, spiritlessly, spunklessly,
   tolerably, unconcernedly, uninterestedly, with indifference,
   with utter indifference, without distinction