obedient; easily managed
Docile horses may be easy to manage, but they are generally less intelligent and spirited than rebellious ones.
docere (to show, teach) (Latin)
amenable, complaisant, compliant, docile, tractable
contentious, headstrong, intractable, obstinate, recalcitrant, refractory
docile (adj) = do + cile (+ently) == if sb is docile, he/she will do silently and therefore easily controllable.