فسق
fasaqa
To commit sin, or to follow a course of sinfulness and evil that stops short of apostasy or blasphemy.
What it means
Fasaqa means to depart from obedience to God by sinning, while remaining within the faith. The one who does so is a fāsiq, and the state is fisq or fusūq. The Quran lists three things that God has made hateful to the believer: disbelief, fusūq and disobedience (49:7). The word thus marks a lesser rank than disbelief but a serious one.
Jurists apply the title fāsiq to a Muslim who persists in major sins or openly disregards the law. The Quran tells believers: “If a fāsiq brings you news, verify it” (49:6), and the jurists take from this that the testimony of such a person is to be examined with care. The term does not strip a person of Islam. The term thus marks a grave failing within the community of the faithful.
Often misunderstood as
Translated “wickedness” or “evil”, which can read as unbelief; the term names sinful conduct that falls short of apostasy or blasphemy.
Term and Arabic as listed in Ismail al Faruqi, Toward Islamic English (International Institute of Islamic Thought, 1995), p. 43, listed as FASAQA. The definition is restated here.