The word Jahiliyyah is used to refer to the period before the coming of the Prophet Muhammad ﷺ. It is the state in which the Arabs were before Islam, during which they were ignorant of Allah, His Messengers and His laws, and were boastful of their ancestral nobility, arrogance, ruthlessness and the like. It refers to two things that are combined in this period: jahl (ignorance) and jahaalah (foolishness).
The word Jahiliyyah is a blameworthy word. Ignorance and foolishness together are sufficient for a person to disavow himself of them, even if he has these attributes, and knowledge and guidance are sufficient for a person to feel proud of, if he has these attributes, and even if he does not. Jahiliyyah is ignorance, or lack of knowledge.
To Him belong the keys of the heavens and the earth. And they who disbelieve in the aayaath of Allah - it is those who are the losers. Say, [O Muhammad], "Is it other than Allah that you order me to worship, O ignorant ones (Jahilun)?" Quran Surah Zumar 39:63,64
In brief, Jahiliyyah is derived from Jahl which is lack of knowledge and it is of two kinds:
1. Universal Jahiliyyah, which existed before the Mission of the Messenger ﷺ, and ended with it.
2. Restricted Jahiliyyah, which exists in some countries, cities or persons. Hence, it becomes clear the mistake of those who impute universal Jahiliyyah to this age referring to it as the Jahiliyyah of this century of the like. Whereas the correct statement to say is, 'the Jahiliyyah of some or most of the people of this century.' It is neither correct not permissible to impute universality to it, for universal Jahiliyyah was obliterated by the Mission of the Prophetﷺ.
Shaikh al-Islam Ibn Taymiyyah said:
"He who does not know the truth possesses simple ignorance, but if he believes in other than the truth, his ignorance is compound. If he speaks against the truth knowingly or unknowingly, he is ignorant too. Having clarified this, people, were in an era of ignorance prior to the Mission of the Messenger of Allah ﷺ, for what they used to follow of utterances and deeds were invented by the ignorant and practices by the ignorant.
For example, a man prior to his conversion to Islam, was in Jahiliyyah even though he lived in a Muslim country. But there is no universal, or absolute Jahiliyyah after the Mission of Muhammad ﷺ. There shall always be a victorious band of his Ummah (nation) adhering to the truth until the Final Hour.
Restricted Jahiliyyah, one the other hand, may exist in some Muslims, and in many Muslims. The Messenger of Allah ﷺsaid: "There are four traits of Jahiliyyah in my Ummah."
Al-Haafiz Ibn Hajar(may Allah have mercy on him) said:
Jahiliyyah refers to that which came before Islam. Fath al-Baari.
Al-Mannaawi(may Allah have mercy on him) said:
Jahiliyyah refers to the time before the Prophetﷺwas sent; they called it that because of the extent of their ignorance. Fayd al-Qadeer.
Shaykh Muhammad ibn Salih al-‘Uthaymeen(may Allah have mercy on him) said:
What is meant by Jahiliyyah is the time before the Prophetﷺwas sent, because at that time the people’s ignorance was great; it included ignorance both of the rights of Allah and the rights of His slaves. Al-Qawl al-Mufeed ‘ala Kitaab al-Tawheed; Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen