impenetrable Antonyms

penetrable fathomable easy to solve porose plumbable no sweat like taking candy from a baby kids' stuff easy peasy lemon squeezy as easy as rolling off a log cognisable high-risk vulnerable visible understandable traversable transparent self-explanatory uncomplicated a cakewalk liable to like stealing candy from a baby just like riding a bicycle fairly straightforward easier than rolling off a log as simple as abc as easy as shooting fish in a barrel as easy as beans as easy as abc as easy as falling off a log a breeze as easy as pie unexacting undemanding thin straightforward soft instructive incomplex fordable extricable excretory elementary effortless easy discernible demurrage comprehensible clear clairvoyant