In Islam, the Munāfiqūn ('hypocrites', singular munāfiq) were a group decried in the Quran as outward Muslims who were secretly unsympathetic to the cause of Muslims and actively sought to undermine the Muslim community.

The hypocrisy itself is called nifāq.

Types of hypocrisy

=> Hypocrisy towards God regarding actual faith.

And of the people are some who say, "We believe in Allah and the Last Day," but they are not believers.

They seek to deceive God and the believers but they only deceive themselves, though they do not realize it.

There is a disease in their hearts, to which God has added more: agonizing torment awaits them for their persistent lying.

When it is said to them, ‘Do not cause corruption in the land,’ they say, ‘We are only putting things right,’

but really they are causing corruption, though they do not realize it.

When it is said to them, ‘Believe, as the others believe,’ they say, ‘Should we believe as the fools do?’ but they are the fools, though they do not know it.

And when they meet those who believe, they say, "We believe"; but when they are alone with their evil ones, they say, "Indeed, we are with you; we were only mockers." /al-Baqarah 2:8-14/

=> Hypocrisy towards the tenets of faith:

for example, somebody may believe in God, Judgment Day, accounting, scales of deeds and Hellfire, but not fear them at all or not refrain from committing sins because of them. Yet he claims, "I fear God."

=> Hypocrisy towards others:

somebody is double-faced and double-tongued. He praises someone in their presence, then, behind their back, he denounces them and tries to cause them pain and harm them.

Munāfiqūn in the Qur'an

The Qur'an has many verses discussing Munāfiqūn, referring to them as more dangerous to Muslims than the worst non-Muslim enemies of Islam.