The word(s) "what" appears 845 time(s) in 697 verse(s) in Quran in Mohsin Khan translation.

(251) And what think those who invent a lie against Allah, on the Day of Resurrection? [i.e. Do they think that they will be forgiven and excused! Nay, they will have an eternal punishment in the Fire of Hell]. Truly, Allah is full of Bounty to mankind, but most of them are ungrateful.

(252) Neither you (O Muhammad صلى الله عليه وسلم) do any deed nor recite any portion of the Qur'an, - nor you (mankind) do any deed (good or evil) but We are Witness thereof, when you are doing it. And nothing is hidden from your Lord (so much as) the weight of an atom (or small ant) on the earth or in the heaven. Not what is less than that or what is greater than that but is (written) in a Clear Record. (Tafsir At-Tabari).

(253) They (Jews, Christians and pagans) say: "Allah has begotten a son (children)." Glory is to Him! He is Rich (Free of all needs). His is all that is in the heavens and all that is in the earth. No warrant you have for this. Do you say against Allah what you know not.

(254) They denied him, but We delivered him, and those with him in the ship, and We made them generations replacing one after another, while We drowned those who belied Our Ayat (proofs, evidence, lessons, signs, revelations, etc.). Then see what was the end of those who were warned.

(255) Then after him We sent Messengers to their people. They brought them clear proofs, but they would not believe what they had already rejected beforehand. Thus We seal the hearts of the transgressors (those who disbelieve in the Oneness of Allah and disobey Him).

(256) And when the sorcerers came, Musa (Moses) said to them: "Cast down what you want to cast!"

(257) Then when they had cast down, Musa (Moses) said: "what you have brought is sorcery; Allah will surely make it of no effect. Verily, Allah does not set right the work of Al-Mufsidun (the evil-doers, corrupters).

(258) No doubt! They did fold up their breasts, that they may hide from Him. Surely, even when they cover themselves with their garments, He knows what they conceal and what they reveal. Verily, He is the All-Knower of the (innermost secrets) of the breasts.

(259) And if We delay the torment for them till a determined term, they are sure to say, "what keeps it back?" Verily, on the day it reaches them, nothing will turn it away from them, and they will be surrounded by (or fall in) that at which they used to mock!

(260) So perchance you (Muhammad صلى الله عليه و سلم) may give up a part of what is revealed unto you, and that your breast feels straitened for it because they say, "Why has not a treasure been sent down unto him, or an angel has come with him?" But you are only a warner. And Allah is a Wakil (Disposer of affairs, Trustee, Guardian) over all things.