The Collaborative International Dictionary of English v.0.48:

Superficial \Su`per*fi"cial\, a. [L. superficialis: cf. F.
   superficiel. See Superficies.]
   1. Of or pertaining to the superficies, or surface; lying on
      the surface; shallow; not deep; as, a superficial color; a
      superficial covering; superficial measure or contents;
      superficial tillage.
      [1913 Webster]

   2. Reaching or comprehending only what is obvious or
      apparent; not deep or profound; shallow; -- said
      especially in respect to study, learning, and the like;
      as, a superficial scholar; superficial knowledge.
      [1913 Webster]

            This superficial tale
            Is but a preface of her worthy praise. --Shak.
      [1913 Webster]

            He is a presumptuous and superficial writer.
                                                  --Burke.
      [1913 Webster]

            That superficial judgment, which happens to be right
            without deserving to be so.           --J. H.
                                                  Newman.
      [1913 Webster] -- Su`per*fi"cial*ly, adv. --
      Su`per*fi"cial*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

superficially
    adv 1: in a superficial manner; "he was superficially
           interested"

Moby Thesaurus II by Grady Ward, 1.0:

91 Moby Thesaurus words for "superficially":
   amain, apace, apparently, aridly, as it seems, at first sight,
   at once, barrenly, bloodlessly, by forced marches, colorlessly,
   cursorily, dismally, draggily, drearily, drearisomely, dryly,
   dully, dustily, effetely, emptily, expeditiously, exteriorly,
   externally, feverishly, frivolously, furiously, hand over fist,
   hastily, heavily, helter-skelter, hollowly, hotfoot, hurriedly,
   hurry-scurry, idly, immaterially, immediately, in passing, inanely,
   inconsequentially, insignificantly, insipidly, instantly, jejunely,
   lifelessly, lightly, on the outside, on the run, on the surface,
   openly, ostensibly, out, outside, outwardly, outwards, pallidly,
   pell-mell, pettily, ploddingly, pointlessly, ponderously,
   prima facie, promptly, publically, quickly, seemingly, shallowly,
   slapdash, slowly, speedily, spiritlessly, stodgily, stuffily,
   swiftly, tastelessly, tediously, to all appearances,
   to all seeming, to the eye, triflingly, trivially, unessentially,
   unimportantly, uninterestingly, vapidly, with a rush,
   with all haste, with dispatch, with haste, without