Eleven important terms
Below is a list of the eleven most important terms in Islamic law. These are the eleven categories of rulings, arranged according to their degree of importance.
(1) Al-Fardh - The Obligation
This is a ruling that must be carried out; omitting it is a major sin. It is definitely from either the Quran or the Sunnah. Therefore its denial is a kufr act. Hence it is also known as Fardh Iteqaadi i.e., it is a part of the faith to believe and follow it.
(2) Al-Wajib - The Necessary
This ruling must also be carried out and its omission is a major sin. However, it is different from the obligation since it is not proven by definite evidence, i.e. the proof for it is not conclusive, there is some doubt as to whether Shari'ah is prescribing it as compulsory or is only recommending it. Therefore its denial is not Kufr. Hence it is called Fardh ul Amali, i.e. it is compulsory to act upon it. Examples of Wajib are the Witr prayer after Isha and Eid prayer.
(3) As-Sunnah-ul-Mu'akkadah - The Emphatic Sunnah
This ruling is based on a regular activity or a habit of the blessed Messenger of Allah or the guided Caliphs. The Sunnah is neither obligatory nor necessary but is highly recommended. The Shari'ah commends this action as being good and acceptable. To habitually miss the Sunnah is detestable, since it gives the impression of turning away from the Prophet's (pbuh) practice.
Examples of emphatic Sunnah are saying the Adhan and praying in congregation.
(4) As-Sunnah Ghair ul Mu'akkadah - The Less Emphatic Sunnah
This is a practice of the blessed Messenger or the Caliphs, but unlike the emphatic Sunnah this was not performed regularly by them. Examples include the four units of Sunnah before Asr and Isha.
(5) Al-Mustahab- The Desirable
This is a ruling that the Shari'ah approves of and finds it is agreeable. This includes activities and devotions like voluntary fasting and prayers. It is sometimes called Al-Mandoob (the Recommended), At-Tatawwa (the Voluntary) and Al Adat (the Decent). Performance of any desirable act earns merits and its omission carries no sanctions.
The Five Types of Prohibitions
(6) Al-Haraam- The Unlawful
This is a ruling that forbids something. In other words, it must be avoided. This prohibition is proved by definite text. To regard unlawful as lawful is therefore kufr. To commit the unlawful is a major sin. Examples include drinking alcohol, gambling and adultery.
(7) Al-Makrooh-ut-Tahrimi- The Major Offense
This is a prohibition that is proved by a prescriptive and not a definite text of argument. To ignore this ruling is a sin that is punishable but to regard it permissible is not an act of kufr.
(8) Al-Makrooh ul Tanzeehi- The Minor Offense
This is a ruling that makes something undesirable. It is best to avoid it but there is no harm in doing it. Examples include splashing water on the face during wudu.
(9) Al-Isaa'h- The Offense
This ruling is in between Makrooh-u-Tahrimi and Tanzeehi in terms of importance. It is a sin to do it and doing it on a regular basis is a major sin. Examples are not rinsing the mouth and cleaning the nose during the wudu.
(10) Khilaaf-ul-Awla- The Undesirable
This is the opposite of Mustahab; it is best to avoid it but there is no harm in doing it
(11) Al- Mubaah- The Permissable
This is something neither prescribed nor prohibited by the Shari'ah; it carries no reward or any punishment. This ruling derived from the Islamic principal that basically everything is permissible unless it is prohibited.