The word(s) "understand" appears 127 time(s) in 127 verse(s) in Quran in Abdullah Yusuf Ali translation.

(21) So also did We show Abraham the power and the laws of the heavens and the earth, that he might (with understanding) have certitude.

(22) It is He Who hath produced you from a single person: here is a place of sojourn and a place of departure: We detail Our signs for people who understand.

(23) Say: Who hath forbidden the beautiful (gifts) of Allah, which He hath produced for His servants, and the things, clean and pure, (which He hath provided) for sustenance? Say: They are, in the life of this world, for those who believe, (and) purely for them on the Day of Judgment. Thus do We explain the signs in detail for those who understand.

(24) He will say: "Enter ye in the company of the peoples who passed away before you - men and jinns, - into the Fire." Every time a new people enters, it curses its sister-people (that went before), until they follow each other, all into the Fire. Saith the last about the first: "Our Lord! it is these that misled us: so give them a double penalty in the Fire." He will say: "Doubled for all": but this ye do not understand.

(25) But when good (times) came, they said, "This is due to us;" When gripped by calamity, they ascribed it to evil omens connected with Moses and those with him! Behold! in truth the omens of evil are theirs in Allah's sight, but most of them do not understand!

(26) After them succeeded an (evil) generation: They inherited the Book, but they chose (for themselves) the vanities of this world, saying (for excuse): "(Everything) will be forgiven us." (Even so), if similar vanities came their way, they would (again) seize them. Was not the covenant of the Book taken from them, that they would not ascribe to Allah anything but the truth? and they study what is in the Book. But best for the righteous is the home in the Hereafter. Will ye not understand?

(27) Many are the Jinns and men we have made for Hell: They have hearts wherewith they understand not, eyes wherewith they see not, and ears wherewith they hear not. They are like cattle,- nay more misguided: for they are heedless (of warning).

(28) For the worst of beasts in the sight of Allah are the deaf and the dumb,- those who understand not.

(29) But what plea have they that Allah should not punish them, when they keep out (men) from the sacred Mosque - and they are not its guardians? No men can be its guardians except the righteous; but most of them do not understand.

(30) O Prophet! rouse the Believers to the fight. If there are twenty amongst you, patient and persevering, they will vanquish two hundred: if a hundred, they will vanquish a thousand of the Unbelievers: for these are a people without understanding.