penetrable

Etymology

From Middle English penetrable, penytrable, from Old French penetrable, from Medieval Latin penetrābilis.

adj

1. Capable of being penetrated, entered, or pierced. Also figuratively.
   On the east the high mountain-chain of Zagros, penetrable only in one or two places, forms a barrier of the most marked character, and is beyond a doubt the natural limit for which we are looking. 1867, George Rawlinson, The Five Great Monarchies of the Ancient Eastern World
   A Boer may know you, but it will take you some time to know him, and when a certain stage in your acquaintance is reached, you may begin to wonder whether his real nature is penetrable at all. 1900, Arthur M. Mann, The Boer in Peace and War
   A capacity is cognitively penetrable in this sense if that capacity is affected by the subject's knowledge or ignorance of the domain. 1996, Peter Carruthers, Peter K. Smith, Theories of Theories of Mind