impregnable

a. 无法攻取的, 坚强不屈的, 驳不倒的

impregnable

adj.（形容词）
Impossible to capture or enter by force:
固若金汤的：不能被攻占或武力进入的：
例句：
an impregnable fortress.
固若金汤的堡垒

Difficult or impossible to attack, challenge, or refute with success:
无懈可击的：不能或很难攻击、挑战或驳倒的：
例句：
an impregnable argument.
无懈可击的辩论


来源：
Middle English
中古英语
from Old French imprenable
源自 古法语 imprenable
in- [not] from Latin in- * see in-
in- [不] 源自 拉丁语 in- *参见 in-
pregnable [pregnable] * see pregnable
pregnable [可攻克的，易受伤害的] *参见 pregnable

impregnable
impregnable 2

adj.（形容词）
Capable of being impregnated.
可以受孕的

来源：
impregn(ate)
impregn(ate)
-able
-able