Why the Devil is called Shaytan?

In the Arabic language, Shaytan is derived from Shatana, which means the far thing. Hence, the Shaytan has a different nature than mankind, and his sinful ways are far away from every type of righteousness. It was also said that Shaytan is derived from Shata, (literally `burned'), because it was created from fire. Some scholars said that both meanings are correct, although they state that the first meaning is more plausible. Further, Siybawayh (the renowned Arab linguistic) said, "The Arabs say, `So-and-so has Tashaytan,' when he commits the act of the devils. If Shaytan was derived from Shata, they would have said, Tashayyata (rather than Tashaytan).'' Hence, Shaytan is derived from the word that means, far away. This is why they call those who are rebellious (or mischievous) from among the Jinns and mankind a `Shaytan'. Allah said,

(And so We have appointed for every Prophet enemies ـ Shayatin (devils) among mankind and Jinn, inspiring one another with adorned speech as a delusion (or by way of deception)) (6:112).

In addition, the Musnad by Imam Ahmad records that Abu Dharr said that the Messenger of Allah said,

(O Abu Dharr! Seek refuge with Allah from the devils of mankind and the Jinns.) Abu Dharr said, "I asked him , `Are there human devils' He said, (Yes.)'' Furthermore, it is recorded in Sahih Muslim that Abu Dharr said that the Messenger of Allah said,

(The woman, the donkey and the black dog interrupt the prayer (if they pass in front of those who do not pray behind a Sutrah, i.e. a barrier).) Abu Dharr said, "I said, `What is the difference between the black dog and the red or yellow dog' He said,

(The black dog is a devil.).''

Also, Ibn Jarir At-Tabari recorded that `Umar bin Al-Khattab once rode a Berthawn (huge camel) which started to proceed arrogantly. `Umar kept striking the animal, but the animal kept walking in an arrogant manner. `Umar dismounted the animal and said, "By Allah! You have carried me on a Shaytan. I did not come down from it until after I had felt something strange in my heart.'' This Hadith has an authentic chain of narrators.

The Meaning of Ar-Rajim 

Ar-Rajim means, being expelled from all types of righteousness. Allah said,

(And indeed We have adorned the nearest heaven with lamps, and We have made such lamps Rujuman (as missiles) to drive away the Shayatin (devils)) (67:5).

Allah also said,

(Verily, We have adorned the near heaven with the stars (for beauty). And to guard against every rebellious devil. They cannot listen to the higher group (angels) for they are pelted from every side. Outcast, and theirs is a constant (or painful) torment. Except such as snatch away something by stealing, and they are pursued by a flaming fire of piercing brightness) (37:6-10).

Further, Allah said,

(And indeed, We have put the big stars in the heaven and We beautified it for the beholders. And We have guarded it (near heaven) from every Shaytan Rajim (outcast Shaytan). Except him (devil) who steals the hearing then he is pursued by a clear flaming fire.) (15:16-18).

There are several similar Ayat. It was also said that Rajim means, the person who throws or bombards things, because the devil throws doubts and evil thoughts in people's hearts. The first meaning is more popular and accurate.

Source : Tafseer Ibn Kathir