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

(101) And before this was the Scripture of Musa (Moses) as a guide and a mercy. And this is a confirming Book (the Qur'an) in the Arabic language, to warn those who do wrong, and as glad tidings to the Muhsinun (good-doers. See the footnote of V.9:120).

(102) And remember (Hud) the brother of 'Ad, when he warned his people in Al-Ahqaf (the curved sand-hills in the southern part of Arabian Peninsula). And surely, there have passed away warners before him and after him (saying): "Worship none but Allah; truly, I fear for you the torment of a mighty Day (i.e. the Day of Resurrection)."

(103) And (remember) when We sent towards you (Muhammad صلى الله عليه وسلم) a group (three to ten persons) of the jinn, (quietly) listening to the Qur'an. When they stood in the presence thereof, they said: "Listen in silence!" And when it was finished, they returned to their people, as warners.

(104) Verily, We have sent you (O Muhammad صلى الله عليه وسلم) as a witness, as a bearer of glad tidings, and as a warner .

(105) Nay, they wonder that there has come to them a warner (Muhammad صلى الله عليه وسلم) from among themselves. So the disbelievers say: "This is a strange thing!

(106) And the Trumpet will be blown - that will be the Day whereof warning (had been given) (i.e. the Day of Resurrection).

(107) We know best what they say. And you (O Muhammad صلى الله عليه وسلم) are not the one to force them (to Belief). But warn by the Qur'an; him who fears My Threat.

(108) So flee to Allah (from His Torment to His Mercy - Islamic Monotheism). Verily, I (Muhammad صلى الله عليه وسلم) am a plain warner to you from Him.

(109) And set not up (or worship not) any other ilah (god) along with Allah [Glorified be He (Alone), Exalted above all that they associate as partners with Him]. Verily, I (Muhammad صلى الله عليه وسلم) am a plain warner to you from Him.

(110) This (Muhammad صلى الله عليه وسلم) is a warner (Messenger) of the (series of) warners (Messengers) of old.