The Collaborative International Dictionary of English v.0.48:

educable \ed"u*ca*ble\ ([e^]d"[-u]*k[.a]*b'l; 135), a. [Cf. F.
   ['e]ducable.]
   Capable of being educated. "Men are educable." --M. Arnold.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "educable":
   apt, bright, clever, docile, facile, formable, impressionable,
   instructable, intelligent, malleable, moldable, motivated, plastic,
   pliable, quick, ready, receptive, ripe for instruction, schoolable,
   susceptible, teachable, thirsty for knowledge, trainable,
   willing