The word(s) "regret" appears 17 time(s) in 17 verse(s) in Quran in Mohsin Khan translation.

(1) And those who followed will say: "If only we had one more chance to return (to the worldly life), we would disown (declare ourselves as innocent from) them as they have disowned (declared themselves as innocent from) us." Thus Allah will show them their deeds as regrets for them. And they will never get out of the Fire.

(2) O you who believe! Be not like those who disbelieve (hypocrites) and who say to their brethren when they travel through the earth or go out to fight: "If they had stayed with us, they would not have died or been killed," so that Allah may make it a cause of regret in their hearts. It is Allah that gives life and causes death. And Allah is All-Seer of what you do.

(3) Then Allah sent a crow who scratched the ground to show him to hide the dead body of his brother. He (the murderer) said: "Woe to me! Am I not even able to be as this crow and to hide the dead body of my brother?" Then he became one of those who regretted.

(4) And you see those in whose hearts there is a disease (of hypocrisy), they hurry to their friendship, saying: "We fear lest some misfortune of a disaster may befall us." Perhaps Allah may bring a victory or a decision according to His Will. Then they will become regretful for what they have been keeping as a secret in themselves.

(5) So, when they forgot (the warning) with which they had been reminded, We opened for them the gates of every (pleasant) thing, until in the midst of their enjoyment in that which they were given, all of a sudden, We took them (in punishment), and lo! They were plunged into destruction with deep regrets and sorrows.

(6) And when they regretted and saw that they had gone astray, they (repented and) said: "If our Lord have not mercy upon us and forgive us, we shall certainly be of the losers."

(7) And if every person who had wronged (by disbelieving in Allah and by worshipping others besides Allah) possessed all that is on the earth and sought to ransom himself therewith (it will not be accepted), and they would feel in their hearts regret when they see the torment, and they will be judged with justice, and no wrong will be done unto them.

(8) So (as a result of that) they deny (with ungratefulness) that (Allah's Favours) which We have bestowed on them! Then enjoy yourselves (your short stay), but you will come to know (with regrets).

(9) And warn them (O Muhammad صلى الله عليه وسلم) of the Day of grief and regrets, when the case has been decided, while (now) they are in a state of carelessness, and they believe not .

(10) (Allah) said: "In a little while, they are sure to be regretful."