An impregnable fortress is a structure or system that is very difficult to attack or penetrate. This means that the fortress is very difficult to take or break through.
The fortress is impregnable because it's built on a steep hill.
The fortress is impregnable because it's made out of thick walls and a strong foundation.
adjective
immune to attack; incapable of being tampered with
Synonyms:
adjective
incapable of being overcome, challenged or refuted
Synonyms:
adjective
capable of conceiving
Synonyms:
1
In that hearing, Butler protested the Fort was impregnable and unassailable.
2
The cloud is impregnated by rain.
3
The water is then impregnated the sheet.
4
Butler claimed the fort was impregnable.
5
It shouldn't be used to impregnate the egg.
6
He'll marry and impregnate her.
7
The country had to be made impregnable.
8
The fort here is most impregnable.
9
The rapists can't impregnate their victims.
10
In the days of horsepower, this was considered an impregnable redoubt.