Fisq is an Arabic word, linguistically it means Khurooj (to leave or emerge), and in the Sharee'ah(it means) departing from the obedience of Allah. It comprises the total departure from obeying Allah which is applicable to the infidel, and it comprises partial departure of obedience which is imputed to a believer who commits a major sin.
Example: If a person commits zinaa (fornication) he becomes a fasiq (person of fisq). If he persists (continue) upon smoking then he becomes a fasiq. If a person drinks an intoxicant only once he becomes a faasiq because this is a major sin. (“Sharh of Safaariniyyah ”of Muhammad ibn Saalih al ‘Uthaymeen rahimahullaah , quoted in Mu’jam at Ta’reefaat p328 )
It comes from the root word, "Fa-Seen-Qaaf (ف س ق) which is a verb in Arabic and its doer is noun ie, Fasiq.
And We have certainly revealed to you aayaath [which are] clear proofs, and no one would deny them except the defiantly disobedient (Fasiqun). Quran Surah Baqarah 2:99
Fisq is of two categories
a. Which constitutes apostasy, i.e. infidelity; in that case a Kafir is called Fasiq, as Allah called Iblees saying: "And disobeyed (Fasaqa) the command of his Rabb." Quran Surah al-Kahf 18: 50
This type of Fisq on the part of Iblees constituted infidelity. And Allah says: "And for those who are disobedient (Fasaqu), their abode will be the Fire." Quran Surah as-Sajdah 32: 20
Allah meant the infidels by 'disobedient' as indicated by His (next) Words: "Whenever they want to come out of it (the Fire) they will be turned back into it, and it will be said to them, 'Taste the punishment of the Fire which you used to deny." Quran Surah as-Sajda 32: 20
b. Although disobedient Muslim is called 'Fasiq', but his Fisq does not cast him out of the folds of Islam, such as those to whom Allah refers in the following verse: "And those who calumniate chaste women and do not bring four witnesses, flog them with eighty lashes, and never accept their testification thereafter, and it is they that are the Fasiq." Quran Surah an-Noor 24: 4
Allah also says: "So whoever decides to perform the pilgrimage in these months, should remember that there is no foul talk, not any Fusuq nor argument during the Hajj season." Quran Surah al-Baqarah 2: 197
Originally written byShaikh Salih al-Fawzaan