The word(s) "heedlessness" appears 2 time(s) in 2 verse(s) in Quran in Muhammad Pickthal translation.

(1) Their reckoning draweth nigh for mankind, while they turn away in heedlessness.

(سورة الأنبياء, Al-Anbiyaa, Chapter #21, Verse #1)
(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)

(2) (And unto the evil-doer it is said): Thou wast in heedlessness of this. Now We have removed from thee thy covering, and piercing is thy sight this day.

(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)