Source : Webster's Revised Unabridged Dictionary (1913)

Sensitive \Sen"si*tive\, a. [F. sensitif. See {Sense}.]
   1. Having sense of feeling; possessing or exhibiting the
      capacity of receiving impressions from external objects;
      as, a sensitive soul.

   2. Having quick and acute sensibility, either to the action
      of external objects, or to impressions upon the mind and
      feelings; highly susceptible; easily and acutely affected.

            She was too sensitive to abuse and calumny.
                                                  --Macaulay.

   3.
      (a) (Mech.) Having a capacity of being easily affected or
          moved; as, a sensitive thermometer; sensitive scales.
      (b) (Chem. & Photog.) Readily affected or changed by
          certain appropriate agents; as, silver chloride or
          bromide, when in contact with certain organic
          substances, is extremely sensitive to actinic rays.

   4. Serving to affect the sense; sensible. [R.]

            A sensitive love of some sensitive objects.
                                                  --Hammond.

   5. Of or pertaining to sensation; depending on sensation; as,
      sensitive motions; sensitive muscular motions excited by
      irritation. --E. Darwin.

   {Sensitive fern} (Bot.), an American fern ({Onoclea
      sensibilis}), the leaves of which, when plucked, show a
      slight tendency to fold together.

   {Sensitive flame} (Physics), a gas flame so arranged that
      under a suitable adjustment of pressure it is exceedingly
      sensitive to sounds, being caused to roar, flare, or
      become suddenly shortened or extinguished, by slight
      sounds of the proper pitch.

   {Sensitive joint vetch} (Bot.), an annual leguminous herb
      ({[AE]schynomene hispida}), with sensitive foliage.

   {Sensitive paper}, paper prepared for photographic purpose by
      being rendered sensitive to the effect of light.

   {Sensitive plant}. (Bot.)
      (a) A leguminous plant ({Mimosa pudica}, or {M.
          sensitiva}, and other allied species), the leaves of
          which close at the slightest touch.
      (b) Any plant showing motions after irritation, as the
          sensitive brier ({Schrankia}) of the Southern States,
          two common American species of Cassia ({C. nictitans},
          and {C. Cham[ae]crista}), a kind of sorrel ({Oxalis
          sensitiva}), etc.

Source : WordNet®

sensitive
     adj 1: responsive to physical stimuli; "a mimosa's leaves are
            sensitive to touch"; "a sensitive voltmeter";
            "sensitive skin"; "sensitive to light" [ant: {insensitive}]
     2: having acute mental or emotional sensibility; "sensitive to
        the local community and its needs" [ant: {insensitive}]
     3: able to feel or perceive; "even amoeba are sensible
        creatures"; "the more sensible p{ enveloping(a),
        shrouding(a), concealing,& (concealing by enclosing or
        wrapping as if in something that is not solid; "the
        enveloping darkness"; "hills concealed by shrouding
        mists") }arts of the skin" [syn: {sensible}] [ant: {insensible}]
     4: hurting; "the tender spot on his jaw" [syn: {sore}, {tender}]
     5: used officially of classified information or matters
        affecting national security