inappreciable

from WordNet (r) 3.0 (2006)

inappreciable
    adj 1: too small to make a significant difference;
           "inappreciable fluctuations in temperature"

from The Collaborative International Dictionary of English v.0.48

Inappreciable \In`ap*pre"ci*a*ble\, a. [Pref. in- not +
   appreciable: cf. F. inappr['e]ciable.]
   Not appreciable; too small to be perceived; incapable of
   being duly valued or estimated. --Hallam.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

53 Moby Thesaurus words for "inappreciable":
      atomic, back-burner, corpuscular, dinky, dispensable, embryonic,
      evanescent, germinal, granular, immaterial, impalpable,
      imperceptible, imponderable, inadequate, inconsequential,
      inconsiderable, indiscernible, inessential, inferior,
      infinitesimal, insensible, insignificant, insufficient, intangible,
      invisible, irrelevant, little, microcosmic, microscopic, minor,
      minute, molecular, negligible, nonessential, not vital, petit,
      scanty, scrimpy, skimpy, small, subatomic, technical, tenuous,
      thin, ultramicroscopic, unapparent, unappreciable, unessential,
      unimpressive, unnoteworthy, unobservable, unperceivable,
      unseeable