The word(s) "lighten" appears 16 time(s) in 16 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) These are the people who buy the life of this world at the price of the Hereafter: their penalty shall not be lightened nor shall they be helped.

(2) They will abide therein: Their penalty will not be lightened, nor will respite be their (lot).

(3) In that will they dwell; nor will their penalty be lightened, nor respite be (their lot);-

(4) Then if they reject thee, so were rejected messengers before thee, who came with Clear Signs, Books of dark prophecies, and the Book of Enlightenment.

(5) Allah doth wish to lighten your (difficulties): For man was created Weak (in flesh).

(6) For the present, Allah hath lightened your (task), for He knoweth that there is a weak spot in you: But (even so), if there are a hundred of you, patient and persevering, they will vanquish two hundred, and if a thousand, they will vanquish two thousand, with the leave of Allah: for Allah is with those who patiently persevere.

(7) We have made the Night and the Day as two (of Our) Signs: the Sign of the Night have We obscured, while the Sign of the Day We have made to enlighten you; that ye may seek bounty from your Lord, and that ye may know the number and count of the years: all things have We explained in detail.

(8) Yet there is among men such a one as disputes about Allah, without Knowledge, without Guidance, and without a Book of Enlightenment,-

(9) Say: See ye? If Allah were to make the night perpetual over you to the Day of Judgment, what god is there other than Allah, who can give you enlightenment? Will ye not then hearken?

(10) Do ye not see that Allah has subjected to your (use) all things in the heavens and on earth, and has made his bounties flow to you in exceeding measure, (both) seen and unseen? Yet there are among men those who dispute about Allah, without knowledge and without guidance, and without a Book to enlighten them!