形容詞 impassable:

1. incapable of being passed
   同義詞：unpassable

1. The forest was almost impassable.
   森林幾乎不可逾越。
2. The soldiers moving through the area had to struggle against the bad weather, which could render the primitive roads impassable.
   士兵們在穿越那一地帶時，必須與惡劣氣候抗?fàn)帲驗閻毫託夂蚩赡苁沟媚切┰嫉牡缆纷屓藷o法通行。
3. When the road became impassable, we had to ditch the car and walk.
   道路無法通行時，我們只好棄車步行。

im.pass.a.ble

adj.（形容詞）
Impossible to pass, cross, or overcome:
不能通行的；不可逾越的：不可能通行、穿越或克服的：
例句：
impassable roads; impassable problems.
不能通行的道路；不能克服的問題

【引伸】
impass.abil.ity 或
impass.ableness
n.（名詞）
impass.ably
adv.（副詞）