The word(s) "unbelief" appears 28 time(s) in 26 verse(s) in Quran in Muhammad Habib Shakir translation.

(21) Postponing (of the sacred month) is only an addition in unbelief, wherewith those who disbelieve are led astray, violating it one year and keeping it sacred another, that they may agree in the number (of months) that Allah has made sacred, and thus violate what Allah has made sacred; the evil of their doings is made fairseeming to them; and Allah does not guide the unbelieving people.

(22) They swear by Allah that they did not speak, and certainly they did speak, the word of unbelief, and disbelieved after their Islam, and they had determined upon what they have not been able to effect, and they did not find fault except because Allah and His Apostle enriched them out of His grace; therefore if they repent, it will be good for them; and if they turn back, Allah will chastise them with a painful chastisement in this world and the hereafter, and they shall not have in the land any guardian or a helper.

(23) The dwellers of the desert are very hard in unbelief and hypocrisy, and more disposed not to know the limits of what Allah has revealed to His Apostle; and Allah is Knowing, Wise.

(24) And those who built a masjid to cause harm and for unbelief and to cause disunion among the believers and an ambush to him who made war against Allah and His Apostle before; and they will certainly swear: We did not desire aught but good; and Allah bears witness that they are most surely liars.

(25) He it is Who made you rulers in the land; therefore whoever disbelieves, his unbelief is against himself; and their unbelief does not increase the disbelievers with their Lord in anything except hatred; and their unbelief does not increase the disbelievers in anything except loss.

(26) And know that among you is Allah's Apostle; should he obey you in many a matter, you would surely fall into distress, but Allah has endeared the faith to you and has made it seemly in your hearts, and He has made hateful to you unbelief and transgression and disobedience; these it is that are the followers of a right way.