The word(s) "grievous" appears 89 time(s) in 89 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) In their hearts is a disease; and Allah has increased their disease: And grievous is the penalty they (incur), because they are false (to themselves).

(2) And remember We appointed forty nights for Moses, and in his absence ye took the calf (for worship), and ye did grievous wrong.

(3) After this it is ye, the same people, who slay among yourselves, and banish a party of you from their homes; assist (Their enemies) against them, in guilt and rancour; and if they come to you as captives, ye ransom them, though it was not lawful for you to banish them. Then is it only a part of the Book that ye believe in, and do ye reject the rest? but what is the reward for those among you who behave like this but disgrace in this life?- and on the Day of Judgment they shall be consigned to the most grievous penalty. For Allah is not unmindful of what ye do.

(4) O ye of Faith! Say not (to the Messenger) words of ambiguous import, but words of respect; and hearken (to him): To those without Faith is a grievous punishment.

(5) Those who conceal Allah's revelations in the Book, and purchase for them a miserable profit,- they swallow into themselves naught but Fire; Allah will not address them on the Day of Resurrection. Nor purify them: grievous will be their penalty.

(6) As to those who deny the Signs of Allah and in defiance of right, slay the prophets, and slay those who teach just dealing with mankind, announce to them a grievous penalty.

(7) As for those who sell the faith they owe to Allah and their own plighted word for a small price, they shall have no portion in the Hereafter: Nor will Allah (Deign to) speak to them or look at them on the Day of Judgment, nor will He cleans them (of sin): They shall have a grievous penalty.

(8) As to those who reject Faith, and die rejecting,- never would be accepted from any such as much gold as the earth contains, though they should offer it for ransom. For such is (in store) a penalty grievous, and they will find no helpers.

(9) Those who purchase Unbelief at the price of faith,- not the least harm will they do to Allah, but they will have a grievous punishment.

(10) Think not that those who exult in what they have brought about, and love to be praised for what they have not done,- think escape the penalty. For them is a penalty grievous indeed.