impenetrable

详细解释:a. 不能通过的, 不可理喻的, 费解的, 顽固的

词型变化：

副词:impenetrably名词:impenetrableness

英语解释：

形容词 impenetrable:

not admitting of penetration or passage into or throughpermitting little if any light to pass through because of denseness of matter同义词：dense, heavy