Fasiq (Arabic: فاسق) is an Arabic term referring to someone who violates Islamic law. As a fasiq is considered unreliable, his testimony is not accepted in Islamic courts. The terms fasiq and fisq are sometime rendered as "impious", "venial sinner", or "depraved".
The jurist Wasil ibn Ata (700-748 CE) submitted that a fasiq remained a member of Muslim society, so retained rights to life and property though he could not hold a religious position. This opinion set him at odds with Mu'tazilite jurists who considered a fasiq to be a munafiq (hypocrite), and the Kharijites who considered the fasiq a kafir.
To the Kharijites "faith without works" was worthless, so one who professed Islam yet sinned was fasiq, and thus a kafir.