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

(1) Seek they other than the religion of Allah, when unto Him submitteth whosoever is in the heavens and the earth, willingly or unwillingly, and unto Him they will be returned.

(سورة آل عمران, Aal-i-Imraan, Chapter #3, Verse #83)
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(2) Say: Pay (your contribution), willingly or unwillingly, it will not be accepted from you. Lo! ye were ever froward folk.

(سورة التوبة, At-Tawba, Chapter #9, Verse #53)
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(3) And unto Allah falleth prostrate whosoever is in the heavens and the earth, willingly or unwillingly, as do their shadows in the morning and the evening hours.

(سورة الرعد, Ar-Ra'd, Chapter #13, Verse #15)
(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)