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

(1) Their reckoning has drawn near to men, and in heedlessness are they turning aside.

(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 the true promise shall draw nigh, then lo! the eyes of those who disbelieved shall be fixedly open: O woe to us! surely we were in a state of heedlessness as to this; nay, we were unjust.

(سورة الأنبياء, Al-Anbiyaa, Chapter #21, Verse #97)
(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)