The Qur'an uses the word kufr to denote people who cover up or hide realities. The Qur'an uses this word to identify those who denied Allah's favors by not accepting His Dominion and Authority. Kufr thus is an antonym for iman or disbelief in Allah and a kafir is a non-believer. This type of kufr is called al-kufr al-akbar or major kufr. There are many types of al-kufr al-akbar:
- Kufr ul-'Inad: Disbelief out of stubborness. This applies to someone who knows the truth and admits to knowing the truth and admits to knowing it with his tongue, but refuses to accept it and refrains from making a declaration. Allah, subhanahu wa ta'ala, says, "Throw into Hell every stubborn disbeliever." [Surah Qaf (50), ayah 24]
- Kufr ul-Inkar: Disbelief out of denial. This applies to someone who denies with both heart and tongue. Allah, subhanahu wa ta'ala, says, "They recognize the favors of Allah, yet they deny them. Most of them are disbelievers." [Surah Nahl (16), ayah 83]
- Kufr ul-Kibr: Disbelief out of arrogance and pride. The disbelief by the devils (e.g. Iblis) is an example of this type of kufr.
- Kufr ul-Juhud: Disbelief out of rejection.This applies to someone who aknowledges the truth in his heart, but rejects it with his tongue. This types of kufr is applicable to those who calls themselves Muslims but who reject any necessary and accepted norms of Islam such as salat and zakat. Allah, subhanahu wa ta'ala, says, "They denied them (i.e. the signs) even though their hearts believed in them, out of spite and arrogance." [Surah Naml (27), ayah 14]
- Kufr ul-Nifaq: Disbelief out of hypocrisy.This applies to someone who pretends to be a believer but conceals his disbelief. Such a person is called a munafiq or hypocrite. Allah, subhanahu wa ta'ala, says, "Verily the hypocrites will be in the lowest depths of Hell. You will find no one to help them." [SurahAn-Nisa (4), ayah 145]
- Kufr ul-Istihal: Disbelief out of trying to make haram into halal. This applies to someone who accepts as lawful (halal) that which Allah has made unlawful (haram) like alcohol or adultery. Only Allah, subhanahu wa ta'ala, has the prerogative to make things halal and haram and those who seek to interfere with His right are like rivals to Him and therefore fall outside the boundries of faith.
- Kufr ul-Kurh: Disbelief out of detesting any of Allah's Commands. Allah, subhanahu wa ta'ala, says, "Perdition (destruction) has been consigned to those who disbelieve and He will render their actions void. This is because they are averse to that which Allah has revealed so He has made their actions fruitless." [Surah Muhammad (47), ayah 8-9]
- Kufr ul-Istihzaha: Disbelief due to mockery and derision. Allah, subhanahu wa ta'ala, says, "Say: Was it at Allah, His signs and His apostles that you were mocking? Make no excuses. You have disbelieved after you have believed." [Surah Taubah (9), ayah 65-66]
- Kufr ul-I'radh: Disbelief due to avoidance. This applies to those who turn away and avoid the truth. Allah, subhanahu wa ta'ala, says, "And who is more unjust than he who is reminded of his Lord's Signs but then turns away from them. Then he forgets what he has sent forward (for the Day of Judgment)." [Surah Kahf (18), ayah 57]
- Kufr ul-Istibdal: Disbelief because of trying to substitute Allah's Laws. This could take the form of (a) rejection of Allah's Law (shari'ah) without denying it, (b) denial of Allah's law and therefore rejecting it, or (c) substituting Allah's laws with man-made laws. Allah, subhanahu wa ta'ala, says, "Or have they partners with Allah who have instituted for them a religion which Allah has not allowed." [Surah Shura (42), ayah 8] Allah, subhanahu wa ta'ala, says, "Say not concerning that which your tongues put forth falsely (that) is lawful and this is forbidden so as to invent a lie against Allah. Verily, those who invent a lie against Allah will never prosper." [Surah Nahl (16), ayah 116]
Adapted from Tafsir Ibn Kathir