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

(41) By Allah, We (also) sent (Our messengers) to Peoples before thee; but Satan made, (to the wicked), their own acts seem alluring: He is also their patron today, but they shall have a most grievous penalty.

(42) Those who believe not in the Signs of Allah,- Allah will not guide them, and theirs will be a grievous Penalty.

(43) (In such falsehood) is but a paltry profit; but they will have a most grievous Penalty.

(44) And to those who believe not in the Hereafter, (it announceth) that We have prepared for them a Penalty grievous (indeed).

(45) No knowledge have they of such a thing, nor had their fathers. It is a grievous thing that issues from their mouths as a saying what they say is nothing but falsehood!

(46) They will abide in this (state): and grievous will the burden be to them on that Day,-

(47) And thus do We recompense him who transgresses beyond bounds and believes not in the Signs of his Lord: and the Penalty of the Hereafter is far more grievous and more enduring.

(48) As to those who have rejected (Allah), and would keep back (men) from the Way of Allah, and from the Sacred Mosque, which We have made (open) to (all) men - equal is the dweller there and the visitor from the country - and any whose purpose therein is profanity or wrong-doing - them will We cause to taste of a most grievous Penalty.

(49) Those who brought forward the lie are a body among yourselves: think it not to be an evil to you; On the contrary it is good for you: to every man among them (will come the punishment) of the sin that he earned, and to him who took on himself the lead among them, will be a penalty grievous.

(50) Were it not for the grace and mercy of Allah on you, in this world and the Hereafter, a grievous penalty would have seized you in that ye rushed glibly into this affair.