Shaitaan

In Islam, the devil is called Shayṭān, (Arabic: شيطان‎‎, plural: شياطين shayāṭīn) and refers to all evil forces under leadership of the archdevil known as Iblīs, who was cast out of heaven, after he refused to prostrate before Adam.

The primary characteristic of Iblis is hubris; not only did he deem himself a superior creation to Adam, he also demonstrated arrogance by challenging Allah's judgment in commanding him to prostrate. His primary activity is to incite humans and jinn to commit evil through deception, which is referred to as "whispering into the hearts." The Quran mentions that satans are the assistants of those who disbelieve in God: "We have made the evil ones friends to those without faith."

The term Iblis (Arabic: إِبْلِيس‎‎) may have derived from Ancient Greek διάβολος (diábolos), also the ultimate source of English 'devil.' Or it may derive from the Arabic verbal root بَلَسَ (balasa, "he despaired"). The term Shaytan (Arabic: شَيْطَان‎‎) has the same origin as Hebrew שָׂטָן (Sātān), source of the English Satan.

...
Wikipedia