- strong enough to resist or withstand attack; not to be taken by force, unconquerable: an impregnable fort.
- not to be overcome or overthrown: an impregnable argument.
Origin of impregnable1
SynonymsSee more synonyms on Thesaurus.com
Examples from the Web for impregnability
That is an astonishing spell of impregnability, one that looked set to last through to a penalty shoot-out tonight.Germany Wins, World Cup Justice Is Served
July 13, 2014
If any spot can impress the notion of impregnability it is Kuffstein.Maurice Tiernay Soldier of Fortune
Charles James Lever
Of course his impregnability gave rise to all manner of stories.The New Tenant
E. Phillips Oppenheim
But its impregnability could not offset its gross imprudence.Benjamin Franklin
John Torrey Morse, Jr.
These were old and had not been repaired, since the Saguntines trusted in the impregnability of the steeps.Snnica
Vicente Blasco Ibez
If any spot can impress the notion of impregnability, it is Kuffstein.
- unable to be broken into or taken by forcean impregnable castle
- unable to be shaken or overcomeimpregnable self-confidence
- incapable of being refutedan impregnable argument
- able to be impregnated; fertile
Word Origin and History for impregnability
early 15c., imprenable "impossible to capture," from Middle French imprenable "invulnerable," from assimilated form of in- "not, opposite of" (see in- (1)) + Old French prenable "assailable, vulnerable" (see pregnable). With intrusive -g- 16c., on model of deign, reign, etc. Related: Impregnability.