Jahiliyyah

The meaning given by many people to the term jahiliyyah is "the time prior Islam". While the time prior to Islam is called Jahiliyyah restricting jahiliyyah to the time before RasulAllah, sallAllahu alayhi wa sallam, was sent is a huge mistake which opens the doors to even bigger mistakes.

Jahiliyyah literally means ignorance. Technically, it means an ignorance of Tawhid (monotheism) and divine law and absence of religious guidance as a result of which corruption dominates the life of a given people. The word Jahiliyyah refers to two things that are combined in this period: jahl (ignorance) and jahaalah (foolishness).

The term denotes any government system, ideology, or institution based on values other than those referring to Allah ta’ala.

Then is it the judgement of the jahiliyyah they desire? But who is better than Allah in judgement for a people who are certain [in faith]. (Surah al Maidah 5/50)

Jahiliyyah is the rule of humans by humans because it involves making some humans servants of others, rebelling against service to Allah, rejecting Allah’s divinity (uluhiyyah) and, in view of this rejection, ascribing divinity to some humans and serving them apart from Allah ta’ala. People - in any time and any place are either governed by Allah’s Shariah - entirely, without any reservations - accepting it and submitting to it, in which case they are following Allah’s religion, or they are governed by a Shari'ah invented by humans, in whatever form, and accept it. In that case they are in jahiliyyah. 

The term jahiliyyah is mentioned 4 times in the Qur'an.

In Surah Al-i Imran the term is used in the meaning of ignorant system of belief.

Then after distress, He sent down upon you security [in the form of] drowsiness, overcoming a faction of you, while another faction worried about themselves, thinking of Allah other than the truth - the thought of jahiliyya, saying, "Is there anything for us [to have done] in this matter?" Say, "Indeed, the matter belongs completely to Allah." (Al-i Imran 3/154)

Therefore the characteristic of the jahiliyyah is, that it is not based on knowledge and revelation but it is based on ignorance and presumption.

In Surah al Fath the term jahiliyyah is used in the meaning of ignorant way of life, ignorant bigotry and barbarism.

When those who disbelieved had put into their hearts pride and haughtiness - the pride and haughtiness of the jahiliyyah Allah sent down His tranquillity upon His Messenger and upon the believers. (Fath 48/26)

Therefore the jahiliyyah has it's own non-Islamic way of life, life style and worldview.

In Surah al Maidah jahiliyyah means judgment, government and understanding of state.

Then is it the judgement of the jahiliyyah they desire? But who is better than Allah in judgement for a people who are certain [in faith]. (al Maidah 5/50)

This means every judgment, governance, and administration that is not based on the rules and laws of Allah is jahiliyyah.

In Surah al Ahzab the term refers to the immorality in the jahiliyyah.

And abide in your houses and do not display yourselves as [was] the display of the former times of jahiliyya. (Ahzab 33/33)

Therefore every behaviour which is incompatible with Islamic morals and every dress-code is jahiliyyah.

So everything which is the opposite of Islam is jahiliyyah. Jahiliyyah is the name for every system and belief besides Islam.