The word(s) "warn" appears 150 time(s) in 135 verse(s) in Quran in Mohsin Khan translation.

(11) So, when they forgot (the warning) with which they had been reminded, We opened for them the gates of every (pleasant) thing, until in the midst of their enjoyment in that which they were given, all of a sudden, We took them (in punishment), and lo! They were plunged into destruction with deep regrets and sorrows.

(12) And We send not the Messengers but as givers of glad tidings and as warners. So whosoever believes and does righteous good deeds, upon such shall come no fear, nor shall they grieve.

(13) And warn therewith (the Qur'an) those who fear that they will be gathered before their Lord, when there will be neither a protector nor an intercessor for them besides Him, so that they may fear Allah and keep their duty to Him (by abstaining from committing sins and by doing all kinds of good deeds which He has ordained).

(14) And this (the Qur'an) is a blessed Book which We have sent down, confirming (the revelations) which came before it, so that you may warn the Mother of Towns (i.e. Makkah) and all those around it. Those who believe in the Hereafter believe in it (the Qur'an), and they are constant in guarding their Salat (prayers).

(15) O you assembly of jinn and mankind! "Did not there come to you Messengers from amongst you, reciting unto you My Verses and warning you of the meeting of this Day of yours?" They will say: "We bear witness against ourselves." It was the life of this world that deceived them. And they will bear witness against themselves that they were disbelievers.

(16) (This is the) Book (the Qur'an) sent down unto you (O Muhammad صلى الله عليه وسلم), so let not your breast be narrow therefrom, that you warn thereby; and a reminder unto the believers.

(17) And the dwellers of Paradise will call out to the dwellers of the Fire (saying): "We have indeed found true what our Lord had promised us; have you also found true, what your Lord promised (warnings)?" They shall say: "Yes." Then a crier will proclaim between them: "The Curse of Allah is on the Zalimun (polytheists and wrong-doers)."

(18) "Do you wonder that there has come to you a Reminder from your Lord through a man from amongst you, that he may warn you, so that you may fear Allah and that you may receive (His) Mercy?"

(19) "Do you wonder that there has come to you a Reminder (and an advice) from your Lord through a man from amongst you to warn you? And remember that He made you successors after the people of Nuh (Noah) and increased you amply in stature. So remember the graces (bestowed upon you) from Allah so that you may be successful."

(20) Do they not reflect? There is no madness in their companion (Muhammad صلى الله عليه وسلم). He is but a plain warner.