impenetrable
adj
1 ~ (to sth) that cannot be entered, passed through, etc 不能通過的; 不可穿越的; 透不過的
an impenetrable jungle, swamp, fortress, etc 無法通過的叢林、 無法經過的沼澤、 不可 越的要塞
impenetrable darkness, fog, etc, ie that cannot be seen through 一片漆黑、 濃霧重鎖
(fig 比喻) his impenetrable ignorance 無法啟迪的愚昧.
2 impossible to understand or solve 不可理解的; 無法解決的
an impenetrable difficulty, mystery, problem, etc 無可克服的困難、 難解之謎、 百思莫解的問題
This history book is completely impenetrable to me. 這本歷史書我完全看不懂.