adjective
- 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.
adjective
- susceptible to impregnation, as an egg.
adjective
- 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
adjective
- able to be impregnated; fertile
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.