The Arabic word dajjal likely comes from the Syriac daggal means liar or lying. Hence, al-dajjal literally means one who conceals the truth with falsehood, the liar or a great deceiver. The word al-masih al-dajjal means to cover (a mangy camel) with tar, because the dajjal will in like manner cover the earth with his adherents. One another view suggests that dajjal is derived from dajala meaning to gild because he will deceive the people by covering up the truth. In the Islamic tradition, dajjal is an evil figure who will lead people astray in the last days and whose advent will be one of the signs of the approaching dooms day. Dajjal or al-Masih al-Dajjal is not mentioned in the Koran, but he figures in numerous hadith.

The equivalent English word for dajjal is Antichrist, which comes from the Greek antichristos, which is composed of two elements: the preposition anti (in place of) and the noun christos (Christ). It indicates that Antichrist is not simply a substitute Christ, but the opponents of the genuine one.

Almost all traditions portray al-Dajjal as a person. In some, he is even said to resemble a specific person whose name was Abdul Uzza bin Qatan. Besides, al-Dajjal is known as ugly, dirty and having only one eye (al-A'war). Anas bin Malik narrates that the Prophet said: "No prophet was sent but he warned his
community against the one-eyed (al-A'war) liar (al-Dajjal)." It is also related that he would first claim to be a prophet, then a god and would command clouds to bring rain. He will command the earth to grow grass. His places of emergence is said to be somewhere between Syria and Iraq. The Sunnis believe that he will be killed by Jesus Christ, while the Shi'its hold his killing by the hands of al-Mahdi.

Some believe that the image of al-Dajjal portrayed in the hadith is irreconcilable with Koranic teachings because the Koran states that the coming of the day of judgement will be sudden (6:31-44, 21:40, 22:25, 43:66). Taftazni (d. 1390), a famous Muslim theologian was first to take its allegorical meaning. He interprets the emergence of al-Dajjal as the dominence of evil and corruption on earth. Some also hold that it is symbolically a movement of irreligion or materialism.