indiscernible

indiscernible
    adj 1: difficult or impossible to perceive or discern; "an
           indiscernible increase in temperature" [ant:
           {discernable}, {discernible}]
    2: barely able to be perceived; "the transition was almost
       indiscernible"; "an almost insensible change" [syn:
       {indiscernible}, {insensible}, {undetectable}]
    

Indiscernible \In`dis*cern"i*ble\, a. [Pref. in- not +
   discernible: cf. F. indiscernable.]
   Not to be discerned; imperceptible; not discoverable or
   visible.
   [1913 Webster]

         Secret and indiscernible ways.           --Jer. Taylor.
   -- {In`dis*cern"i*ble*ness}, n. -- {In`dis*cern"i*bly}, adv.
   Indiscerpibility
    

61 Moby Thesaurus words for "indiscernible":
      alike, atomic, behind the curtain, behind the scenes, camouflaged,
      concealed, corpuscular, disguised, embryonic, evanescent, germinal,
      granular, hidden, impalpable, imperceptible, imponderable,
      inappreciable, indistinct, indistinctive, indistinguishable,
      infinitesimal, insensible, intangible, interchangeable, invisible,
      latent, microcosmic, microscopic, molecular, out of sight, secret,
      sightless, standard, stereotyped, subatomic, submerged, tenuous,
      thin, ultramicroscopic, unapparent, unappreciable, unbeheld,
      unbeholdable, undifferentiated, undiscernible, undiscriminated,
      undistinguishable, undistinguished, uniform, unnoticed,
      unobservable, unobserved, unperceivable, unperceived, unrealized,
      unseeable, unseen, unviewed, unwitnessed, viewless,
      without distinction