Found just once in the New Testament (Rom. 2:5Rom. 2:5
English: American Standard Version (1901) - ASV
5 but after thy hardness and impenitent heart treasurest up for thyself wrath in the day of wrath and revelation of the righteous judgment of God;

WP-Bible plugin), the Greek adjective “ametanoetos” meant “impenitent” or “unrepentant” (i.e. refusing to change for the better).

All men everywhere are commanded to repent (Acts 17:30Acts 17:30
English: American Standard Version (1901) - ASV
30 The times of ignorance therefore God overlooked; but now he commandeth men that they should all everywhere repent:

WP-Bible plugin) lest they perish (Lk. 13:3Lk. 13:3
English: American Standard Version (1901) - ASV
3 I tell you, Nay: but, except ye repent, ye shall all in like manner perish.

WP-Bible plugin), but some choose to have an “impenitent” heart (Rom. 2:5Rom. 2:5
English: American Standard Version (1901) - ASV
5 but after thy hardness and impenitent heart treasurest up for thyself wrath in the day of wrath and revelation of the righteous judgment of God;

WP-Bible plugin).