unnaturalizable
/(ˌ)ʌnˈnatʃ(ə)rəlʌɪzəbl/ /(ˌ)ʌnˈnatʃ(ə)r(ə)lʌɪzəbl/(also unnaturalisable)
adjective
That cannot or may not be naturalized.
Origin
Mid 19th century; earliest use found in Edward Bulwer-Lytton (1803–1873), writer and politician. From un- + naturalize + -able.