penetrable

adj

1. Capable of being penetrated, entered, or pierced.

   “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.”

2. (figuratively)Capable of being fully understood.

   “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.”

   “A capacity is cognitively penetrable in this sense if that capacity is affected by the subject's knowledge or ignorance of the domain.”