形容詞 impregnable:

1. able to withstand attack
   同義詞：inviolable, secure, strong, unassailable, unattackable
2. capable of conceiving
   同義詞：conceptive
3. incapable of being overcome, challenged or refuted
   同義詞：inexpugnable

1. Immune to attack; impregnable.
   固若金湯攻不破的; 固若金湯的

impregnable

adj.（形容詞）
Impossible to capture or enter by force:
固若金湯的：不能被攻占或武力進入的：
例句：
an impregnable fortress.
固若金湯的堡壘

Difficult or impossible to attack, challenge, or refute with success:
無懈可擊的：不能或很難攻擊、挑戰(zhàn)或駁倒的：
例句：
an impregnable argument.
無懈可擊的辯論

來源：
Middle English
中古英語
from Old French imprenable
源自 古法語 imprenable
in- [not] from Latin in- * see in-
in- [不] 源自 拉丁語 in- *參見 in-
pregnable [pregnable] * see pregnable
pregnable [可攻克的，易受傷害的] *參見 pregnable

impregnable
impregnable 2

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

來源：
impregn(ate)
impregn(ate)
-able
-able