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 are inwardly concealing disbelief—kufr—and actively seek to undermine the Muslim community. A 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).