Munafiq

In Islam, the munafiqun (lit. 'hypocrites', Arabic: منافقون, singular منافق, munāfiq) or false Muslims or false believers are a group decried in the Quran as outward Muslims who were inwardly concealing disbelief ("kufr") and actively sought to undermine the Muslim community. Munafiq is a person who in public and in community shows that he is a Muslim but rejects Islam or speaks against it either in his heart or among the enemies of Islam. The hypocrisy itself is called nifāq (نفاق).