The Collaborative International Dictionary of English v.0.48:

Susceptibility \Sus*cep`ti*bil"i*ty\, n.; pl.
   Susceptibilities. [Cf. F. susceptibilit['e].]
   1. The state or quality of being susceptible; the capability
      of receiving impressions, or of being affected.
      [1913 Webster]

   2. Specifically, capacity for deep feeling or emotional
      excitement; sensibility, in its broadest acceptation;
      impressibility; sensitiveness.
      [1913 Webster]

   Magnetic susceptibility (Physics), the intensity of
      magnetization of a body placed in a uniform megnetic field
      of unit strength. --Sir W. Thomson.
      [1913 Webster]

   Syn: Capability; sensibility; feeling; emotion.
        [1913 Webster]

WordNet (r) 3.0 (2006):

susceptibility
    n 1: the state of being susceptible; easily affected [syn:
         susceptibility, susceptibleness] [ant: immunity,
         unsusceptibility]