In Islam a Jahiliyah is a person who knows the truth, and knows it is the truth, but chooses to ignore it because they like their way better.

This is particularily looked down on in Islam as one of the central tenets of the Islamic mindset is to find and know the truth, about everything.

Many things the west takes for granted now were precious gifts, when Muslims first taught them. The scientific method when anything that didn’t agree with the Church was blasphemy. Modern Medicine when your local barber would be arranging his bloodletting schedule. Algebra when Europeans couldn’t read or count either. While sick people in Europe were walled into their homes, the Muslims had hospitals, with quarantine wards for different diseases, this after Muslim doctors wrote the theory that disease could be spread by microscopic particles.

Muslim scientists and doctors were the cream of Muslim society.When western scientists were burned as heretics Muslim scientists were being paid to live in luxury and continue their research.
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In response to ymelup: Jahiliya has multiple meanings regarding ignorance, you state the meaning of when the Prophet and Sahabi were still kaffir, but had no choice as they did not have the information. The meaning I have posted is of after they delivered the message, when people CHOSE to ignore it and remain kaffir. Jahil comes from Abu-Jahil, a kaffir who fought the Prophet. An Arabic word can have hundreds of meanings.