Definition of inexpugnable in English:

inexpugnable

adjective

  • archaic term for impregnable
    • ‘It evinces an overdiminished but nevertheless inexpugnable desire for moral as well as ethical rectitude.’
    • ‘I mean the inexpugnable belief that every detailed occurrence can be correlated with its antecedents in a perfectly definite manner exemplifying general principles.’
    • ‘The city is fortified with 150 very strong towers, covered over with ceilings from the upper stories of the buildings in its streets like a crypt, and in a measure inexpugnable.’

Origin

Late Middle English: via Old French from Latin inexpugnabilis, from in- not + expugnabilis able to be taken by assault.

Pronunciation:

inexpugnable

/ˌinekˈspyo͞onəb(ə)l//ˌinekˈspəɡnəb(ə)l/