porous          
adjective uk/ˈpɔː.rəs/ us/ˈpɔːr.əs/
 多孔的;能渗漏的
Something that is porous has many small holes, so liquid or air can pass through, especially slowly.
  porous soil with good drainage 有良好排水系统的渗漏性土壤 
 porous brick walls 多孔砖墙 
 a porous polymer membrane 多孔聚合物膜 
  多漏洞的,松懈的
not protected enough to stop people going through
  The border in this region is porous and many refugees have simply walked across. 这个地区的边界管理很松懈,许多难民很容易就越过了。