The Collaborative International Dictionary of English v.0.48:

Sparing \Spar"ing\, a.
   Spare; saving; frugal; merciful. --Bacon.
   [1913 Webster] -- Spar"ing*ly, adv. -- Spar"ing*ness, n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sparingly
    adv 1: to a meager degree or in a meager manner; "these voices
           are meagerly represented at the conference"; "the area is
           slenderly endowed with natural resources" [syn:
           meagerly, sparingly, slenderly, meagrely] [ant:
           amply, fully, richly]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "sparingly":
   cannily, carefully, charily, economically, frugally, husbandly,
   in moderation, meagerly, moderately, poorly, providently,
   prudently, punily, scantily, slightly, sparely, sparsely,
   stintingly, temperately, thin, thriftily, within bounds,
   within compass