The word(s) "sin" appears 521 time(s) in 480 verse(s) in Quran in Mohsin Khan translation.

(341) Giving glad tidings [of Paradise to the one who believes in the Oneness of Allah (i.e. Islamic Monotheism) and fears Allah much (abstains from all kinds of sins and evil deeds) and loves Allah much (performing all kinds of good deeds which He has ordained)], and warning (of punishment in the Hell-Fire to the one who disbelieves in the Oneness of Allah), but most of them turn away, so they hear not.

(342) Then He completed and finished from their creation (as) seven heavens in two Days and He made in each heaven its affair. And We adorned the nearest (lowest) heaven with lamps (stars) to be an adornment as well as to guard (from the devils by using them as missiles against the devils). Such is the Decree of Him the All-Mighty, the All-Knower.

(343) 'Ain-sin-Qaf. [These letters are one of the miracles of the Qur'an, and none but Allah (Alone) knows their meanings].

(344) So unto this (religion of Islam alone and this Qur'an) then invite (people) (O Muhammad صلى الله عليه و سلم), and stand firm [on Islamic Monotheism by performing all that is ordained by Allah (good deeds), and by abstaining from all that is forbidden by Allah (sins and evil deeds)], as you are commanded, and follow not their desires but say: "I believe in whatsoever Allah has sent down of the Book [all the holy Books, - this Qur'an and the Books of the old from the Taurat (Torah), or the Injeel (Gospel) or the Pages of Ibrahim (Abraham)] and I am commanded to do justice among you. Allah is our Lord and your Lord. For us our deeds and for you your deeds. There is no dispute between us and you. Allah will assemble us (all), and to Him is the final return."

(345) And He it is Who accepts repentance from His slaves, and forgives sins, and He knows what you do.

(346) So whatever you have been given is but (a passing) enjoyment for this worldly life, but that which is with Allah (Paradise) is better and more lasting for those who believe (in the Oneness of Allah - Islamic Monotheism) and put their trust in their Lord (concerning all of their affairs).

(347) And those who avoid the greater sins, and Al-Fawahish (illegal sexual intercourse), and when they are angry, forgive.

(348) Verily, the Mujrimun (criminals, sinners, disbelievers) will be in the torment of Hell to abide therein forever.

(349) (But they were aggressive), so he [Musa (Moses)] called upon his Lord (saying): "These are indeed the people who are Mujrimun (disbelievers, polytheists, sinners, criminals)."

(350) From Fir'aun (Pharaoh); verily he was arrogant and was of the Musrifun (those who transgress beyond bound in spending and other things and commit great sins).