inexpugnable w języku angielskim

unassailable▼◼◼◼(secure against attack; impregnable)
adjective
[UK: ˌʌ.nə.ˈseɪ.ləb.l̩] [US: ˌʌ.nə.ˈseɪ.ləb.l̩]

inexpugnable▼(impregnable, unconquerable)
adjective
[UK: ˌɪ.nɪks.ˈpʌɡ.nəbl] [US: ˌɪ.nɪk.ˈspʌɡ.nə.bəl]