Source : Webster's Revised Unabridged Dictionary (1913)

Communicable \Com*mu"ni*ca*ble\, a. [Cf. F. communicable, LL.
   communicabilis.]
   1. Capable of being communicated, or imparted; as, a
      communicable disease; communicable knowledge.

   2. Communicative; free-speaking. [Obs.] --B. Jonson. --
      {Com*mu"ni*ca*ble*ness}, n. -- {Com*mu"ni*ca"bly}, adv.

Source : WordNet®

communicable
     adj 1: (of disease) capable of being transmitted by infection [syn:
             {catching}, {contagious}, {contractable}, {transmissible},
             {transmittable}]
     2: readily communicated; "communicable ideas"