The word(s) "ungrateful" appears 5 time(s) in 3 verse(s) in Quran in Muhammad Pickthal translation.

(1) Lo! the worst of beasts in Allah's sight are the ungrateful who will not believe.

(سورة الأنفال, Al-Anfaal, Chapter #8, Verse #55)
(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) One with whom was knowledge of the Scripture said: I will bring it thee before thy gaze returneth unto thee. And when he saw it set in his presence, (Solomon) said: This is of the bounty of my Lord, that He may try me whether I give thanks or am ungrateful. Whosoever giveth thanks he only giveth thanks for (the good of) his own soul; and whosoever is ungrateful (is ungrateful only to his own soul's hurt). For lo! my Lord is Absolute in independence, Bountiful.

(سورة النمل, An-Naml, Chapter #27, Verse #40)
(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)

(3) Man is (self-)destroyed: how ungrateful!

(سورة عبس, Abasa, Chapter #80, Verse #17)
(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)