The Collaborative International Dictionary of English v.0.48:

Scarce \Scarce\, Scarcely \Scarce"ly\, adv.
   1. With difficulty; hardly; scantly; barely; but just.
      [1913 Webster]

            With a scarce well-lighted flame.     --Milton.
      [1913 Webster]

            The eldest scarcely five year was of age. --Chaucer.
      [1913 Webster]

            Slowly she sails, and scarcely stems the tides.
                                                  --Dryden.
      [1913 Webster]

            He had scarcely finished, when the laborer arrived
            who had been sent for my ransom.      --W. Irving.
      [1913 Webster]

   2. Frugally; penuriously. [Obs.] --Chaucer.
      [1913 Webster]

WordNet (r) 3.0 (2006):

scarcely
    adv 1: only a very short time before; "they could barely hear
           the speaker"; "we hardly knew them"; "just missed being
           hit"; "had scarcely rung the bell when the door flew
           open"; "would have scarce arrived before she would have
           found some excuse to leave"- W.B.Yeats [syn: barely,
           hardly, just, scarcely, scarce]
    2: almost not; "he hardly ever goes fishing"; "he was hardly
       more than sixteen years old"; "they scarcely ever used the
       emergency generator" [syn: hardly, scarcely]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "scarcely":
   a bit, a little, at infrequent intervals, barely, by a hair,
   by an ace, by no means, ever so little, exiguously, extremely,
   faintly, fairly, feebly, hardly, hardly ever, here and there,
   imperfectly, in a measure, in a way, in no way, in places,
   in some measure, in spots, inappreciably, inconsequentially,
   infrequently, insignificantly, just a bit, kind of, lightly,
   little, meagerly, minimally, minutely, negligibly, not at all,
   not hardly, not often, not quite, noway, nowise, on no account,
   only just, piddlingly, pretty, quite, rarely, rather, scantily,
   scarce, scarcely ever, scrimpily, seldom, skimpily, slightly,
   somewhat, sort of, sparsely, sparsim, spottily, stingily,
   tant soit peu, to a degree, to some extent, triflingly, uncommonly,
   under no circumstances, unfrequently, unoften, very, very seldom,
   weakly