From BiblePortal Wikipedia

Vine's Expository Dictionary of OT Words [1]

Nâcham ( נָחַם , 5162), “to repent, comfort.” Nâcham apparently means “to repent” about 40 times and “to comfort” about 65 times in the Old Testament. Scholars assert several views in trying to ascertain the meaning of nâcham by connecting the word to a change of the heart or disposition, a change of mind, a change of purpose, or an emphasis upon the change of one’s conduct.

Most uses of the term in the Old Testament are connected with God’s repentance: “… It repented the Lord that he had made man …” (Gen. 6:6); “And the Lord repented [NASB, “changed his mind”] of the evil which he thought to do unto his people” (Exod. 32:14, KJV). Sometimes the Lord “repented” of the discipline He had planned to carry out concerning His people: “If that nation, against whom I have pronounced, turn from their evil, I will repent of the evil that I thought to do unto them” (Jer. 18:8); “If it do evil in my sight, that it obey not my voice, then I will repent of the good …” (Jer. 18:10); “And rend your heart, and not your garments, and turn unto the Lord your God: for he is gracious and merciful, slow to anger … and repenteth him of evil” (Joel 2:13). In other instances, the Lord changed His mind; obviously, He changed when man changed to make the right choices, but He could not change His attitude toward evil when man continued on the wrong course. As God changed His actions, He always remained faithful to His own righteousness.

In some situations, God was weary of“repenting” (Jer. 15:6), suggesting that there might be a point beyond which He had no choice but to implement His discipline. An instance of this action was in Samuel’s word to Saul, that God took the kingdom from Israel’s first king and intended to give it to another; Samuel declared, “And also the Strength of Israel will not lie nor repent; for he is not a man, that he should repent” (NASB, “change His mind”; 1 Sam. 15:29).

God usually changed His mind and “repented” of His actions because of man’s intercession and repentance of his evil deeds. Moses pleaded with God as the intercessor for Israel: “Turn from thy fierce wrath, and repent of this evil against thy people” (Exod. 32:12). The Lord did that when He “… repented [changed His mind] of the evil which he thought to do unto his people” (Exod. 32:14). As God’s prophet preached to Nineveh, “… God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them …” (Jonah 3:10). In such instances, God “repented,” or changed His mind, to bring about a change of plan. Again, however, God remained faithful to His absolutes of righteousness in His relation to and with man.

Other passages refer to a change (or lack of it) in man’s attitude. When man did not “repent” of his wickedness, he chose rebellion (Jer. 8:6). In the eschatological sense, when Ephraim (as a representative of the northern branch of Israel) will “repent” (Jer. 31:19), God then will have mercy (Jer. 31:20).

Man also expressed repentance to other men. Benjamin suffered greatly from the crime of immorality (Judg. 19-20): “And the children of Israel [eleven tribes] repented them from Benjamin their brother, and said, There is one tribe cut off from Israel this day” (Judg. 21:6; cf. v. 15).

Nâcham may also mean “to comfort.” The refugees in Babylon would be “comforted” when survivors arrived from Jerusalem (Ezek. 14:23); the connection between “comfort” and “repent” here resulted from the calamity God brought upon Jerusalem as a testimony to the truth of His Word. David “comforted” Bathsheba after the death of her child born in sin (2 Sam. 12:24); this probably indicates his repentance of what had happened in their indiscretion.

On the other hand, the word was used in the human sense of “comfort.” Job asked his three companions, “How then comfort ye me in vain seeing in your answers there remaineth falsehood?” (Job 21:34; he meant that their attitude seemed cruel and unfeeling). The psalmist looked to God for “comfort”: “Thou shalt increase my greatness, and comfort me on every side” (Ps. 71:21). In an eschatological sense God indicated that He would “comfort” Jerusalem with the restoration of Israel, as a mother comforts her offspring (Isa. 66:13).

Webster's Dictionary [2]

(1): ( v. i.) To be sorry for sin as morally evil, and to seek forgiveness; to cease to love and practice sin.

(2): ( a.) Prostrate and rooting; - said of stems.

(3): ( a.) Same as Reptant.

(4): ( v. t.) To cause to have sorrow or regret; - used impersonally.

(5): ( v. i.) To feel pain, sorrow, or regret, for what one has done or omitted to do.

(6): ( v. i.) To change the mind, or the course of conduct, on account of regret or dissatisfaction.

(7): ( v. t.) To feel regret or sorrow; - used reflexively.

(8): ( v. t.) To feel pain on account of; to remember with sorrow.

King James Dictionary [3]

RE'PENT, a. L. repo, to creep. Creeping as a repent root.