IPA: //ʌnˈrɛdʒɪnɪt//
KK: /ʌnˈrɛdʒɪnɪt/
Describing someone who is not willing to change or improve, often remaining stubborn or sinful.
Despite many chances to change, he remained unregenerate in his ways.
Unregenerate → It is formed from "un-" (meaning not) and "regenerate" (from Latin "regenerare", meaning to be born again). The word "unregenerate" means not having been born again or not having undergone spiritual renewal.
Think of 'not' ('un-') having been 'born again' ('regenerate') — that's why unregenerate refers to someone who has not experienced spiritual renewal.