The word "penetrably" means that something can be easily penetrated or entered through. Some synonyms for "penetrably" include permeable, porous, absorbent, accessible, and open. A permeable substance allows a fluid or gas to pass through it, while a porous substance has small holes that allow air or liquid to pass through. An absorbent material can soak up liquids or gases, while something that is accessible can be easily reached. Lastly, something that is open allows for entry or easy access. These words can be used interchangeably with "penetrably" to add variety and clarity to your writing.