1 able to withstand attack; "an impregnable fortress"; "fortifications that made the frontier inviolable" [syn: inviolable, secure, strong, unassailable, unattackable]
2 impossible to take by storm [syn: inexpugnable]
- (Of a fortress, wall, etc.) Too strong to be penetrated.
From 1862 the second Impregnable was used as a training ship at Devonport. As training ships were replaced or added to the establishment, each was renamed Impregnable when she took on the role. These ships were originally:
- Howe, launched in 1860, was Impregnable from 1886–1919.
- Inconstant, launched in 1868, was Impregnable II from 1898–1906.
- Black Prince, launched in 1861, was Impregnable III from 1910–1923.
- Circe, launched in 1827, was Impregnable IV from 1916–1922.
- Powerful, launched in 1895, was Impregnable from 1919–1929.
- Andromeda, launched in 1897, was Impregnable II from 1919–1931.
- Caroline, launched in 1882, was Impregnable IV from 1919–1929.
- Ganges, launched in 1821, was Impregnable III from 1922–1929.
deathless, defended, guarded, immortal, impenetrable, imperishable, incontestable, incorruptible, indelible, indestructible, indomitable, ineffaceable, ineradicable, inexpugnable, inextinguishable, insuperable, invincible, inviolable, invulnerable, irresistible, mighty, nonperishable, overpowering, overwhelming, protected, quenchless, resistless, safe, safeguarded, secure, shielded, unassailable, unbeatable, unconquerable, undampable, undefeatable, undestroyable, undying, unquenchable, unsubduable, unsurmountable, unyielding