I. The Verb.
1. metanoeo = to change one's mind, always for the better, and morally. Because of this it is often used in the Imperative (Matt. 3:2; 4:17. Acts 2:38; 3:19). Not merely to forsake sin, but to change one's apprehension regarding it. It occurs thirty-four times. It answers to the Latin resipisco = to recover one's senses, to come to one's self.
2. metamelomai = to regret; to have after care or annoyances at the consequences of an act of sin rather than a deep regret at the cause from want of not knowing better. Hence it is never used in the Imperative. It occurs six time, and in each case (except Matt. 21:29, 32) never in the real Biblical sense of "repentance toward God". It is from meta = after, and melo = to be an object of care. See notes on 2Cor. 7:8 and 10. It is used of Judas Iscariot (Matt. 27:3); negatively of Paul's regret (2Cor. 7:8); and of God (Heb. 7:21).
The Noun, metameleia, is not used in the N.T.
1. metanoia = a real change of mind and attitude
toward sin itself, and the cause of it (not merely the consequence
of it), which affects the whole life and not merely a single act.
It has been defined as a change in our principle of action (Gr. nous)
from what is by nature the exact opposite. It occurs twenty-four
times, and except Heb. 12:17 is a real "repentance toward God". It
is associated with the word of the Holy Spirit, and is connected with the
remission of sins and the promises of salvation.