Source : Webster's Revised Unabridged Dictionary (1913)

      Candidates are . . . not very susceptible of affronts.
                                                  --Cowper.

      I am constitutionally susceptible of noises. --Lamb.
-- {Sus*cep"ti*ble*ness}, n. -- {Sus*cep"ti*bly}, adv.

Source : WordNet®

susceptibleness
     n : the state of being susceptible; easily affected [syn: {susceptibility}]
         [ant: {unsusceptibility}]