From The Collaborative International Dictionary of English v.0.48 [gcide]:
Communicable \Com*mu"ni*ca*ble\ (k[o^]m*m[=u]"n[i^]*k[.a]*b'l),
a. [Cf. F. communicable, LL. communicabilis.]
1. Capable of being communicated, or imparted; as, a
communicable disease; communicable knowledge.
[1913 Webster]
2. Communicative; free-speaking. [Obs.] --B. Jonson. --
Com*mu"ni*ca*ble*ness, n. -- Com*mu"ni*ca"bly, adv.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
communicable
adj 1: (of disease) capable of being transmitted by infection
[syn: catching, communicable, contagious,
contractable, transmissible, transmittable]
2: readily communicated; "communicable ideas"