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

(1) And they say: Our hearts are hardened. Nay, but Allah hath cursed them for their unbelief. Little is that which they believe.

(سورة البقرة, Al-Baqara, Chapter #2, Verse #88)
(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) When they come unto you (Muslims), they say: We believe; but they came in unbelief and they went out in the same; and Allah knoweth best what they were hiding.

(سورة المائدة, Al-Maaida, Chapter #5, Verse #61)
(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)