The word(s) "unmindful" appears 2 time(s) in 2 verse(s) in Quran in Saheeh International translation.

(1) And [when] the true promise has approached; then suddenly the eyes of those who disbelieved will be staring [in horror, while they say], "O woe to us; we had been unmindful of this; rather, we were wrongdoers."

(سورة الأنبياء, Al-Anbiyaa, Chapter #21, Verse #97)
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(2) [It will be said], "You were certainly in unmindfulness of this, and We have removed from you your cover, so your sight, this Day, is sharp."

(سورة ق, Qaaf, Chapter #50, Verse #22)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)