The Collaborative International Dictionary of English v.0.48:

Properly \Prop"er*ly\, adv.
   [1913 Webster]
   1. In a proper manner; suitably; fitly; strictly; rightly;
      as, a word properly applied; a dress properly adjusted.
      --Milton.
      [1913 Webster]

   2. Individually; after one's own manner. [Obs.]
      [1913 Webster]

            Now, harkeneth, how I bare me properly. --Chaucer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

properly
    adv 1: in the right manner; "please do your job properly!";
           "can't you carry me decent?" [syn: properly,
           decently, decent, in good order, right, the
           right way] [ant: improperly]
    2: with reason or justice [syn: by rights, properly]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "properly":
   acceptably, according to use, accurately, adequately,
   advantageously, advisably, aesthetically, amply, appropriately,
   aptly, artistically, as is proper, as is right, becomingly,
   by right, by rights, comme il faut, condignly, congruously,
   conveniently, conventionally, correctly, customarily, decently,
   decorously, deservedly, desirably, disinterestedly,
   dispassionately, duly, elegantly, equally, equitably, evenly,
   expediently, fair, fairly, faultlessly, feasibly, fitly, fittingly,
   flawlessly, genteelly, gracefully, impartially, impersonally,
   in all conscience, in good taste, in reason, inequity, injustice,
   just right, just so, justifiably, justifiedly, justly, meetly,
   nicely, opportunely, orthodoxly, perfectly, politely, practically,
   quietly, right, rightfully, rightly, satisfactorily, seasonably,
   seemly, sic, simply, so, sortably, straight, suitably, tastefully,
   to advantage, traditionally, unobtrusively, upon even terms,
   warrantably, warrantedly, well, with taste, without distinction