inexpugnable

adjective

Impossible to overcome or overthrow by force.

adjective

Impossible to put aside or drive away.

Not expugnable; that cannot be overcome by force, nor taken by assault; unconquerable; impregnable.

adjective

Incapable of being subdued by force; impregnable; unconquerable.

adjective

Impossible to eliminate or destroy; impregnable

adjective

incapable of being overcome, challenged or refuted