Apostasy in Islam (Arabic: ردة, riddah or ارتداد, irtidād) is commonly defined as the abandonment of Islam by a Muslim, in thought, word, or through deed. An apostate from Islam is referred to by using the Arabic and Islamic term murtād (مرتدّ). It includes not only explicit renunciations of the Islamic faith by converting to another religion or abandoning religion altogether, but also blasphemy or heresy, through any action or utterance which implies unbelief, including those who deny a "fundamental tenet or creed" of Islam.