The word(s) "warning" appears 53 time(s) in 52 verse(s) in Quran in Abdullah Yusuf Ali translation.

(11) Say to the Unbelievers, if (now) they desist (from Unbelief), their past would be forgiven them; but if they persist, the punishment of those before them is already (a matter of warning for them).

(12) We sent Noah to his people (with a mission): "I have come to you with a Clear warning:

(13) Here is a Message for mankind: Let them take warning therefrom, and let them know that He is (no other than) One Allah: let men of understanding take heed.

(14) And We gave (Clear) warning to the Children of Israel in the Book, that twice would they do mischief on the earth and be elated with mighty arrogance (and twice would they be punished)!

(15) When the first of the warnings came to pass, We sent against you Our servants given to terrible warfare: They entered the very inmost parts of your homes; and it was a warning (completely) fulfilled.

(16) If ye did well, ye did well for yourselves; if ye did evil, (ye did it) against yourselves. So when the second of the warnings came to pass, (We permitted your enemies) to disfigure your faces, and to enter your Temple as they had entered it before, and to visit with destruction all that fell into their power.

(17) Who receiveth guidance, receiveth it for his own benefit: who goeth astray doth so to his own loss: No bearer of burdens can bear the burden of another: nor would We visit with Our Wrath until We had sent an messenger (to give warning).

(18) And We refrain from sending the signs, only because the men of former generations treated them as false: We sent the she-camel to the Thamud to open their eyes, but they treated her wrongfully: We only send the Signs by way of terror (and warning from evil).

(19) Behold! We told thee that thy Lord doth encompass mankind round about: We granted the vision which We showed thee, but as a trial for men,- as also the Cursed Tree (mentioned) in the Qur'an: We put terror (and warning) into them, but it only increases their inordinate transgression!

(20) And We said thereafter to the Children of Israel, "Dwell securely in the land (of promise)": but when the second of the warnings came to pass, We gathered you together in a mingled crowd.