is an expert of' Islamic jurisprudence (fiqh). Commonly it is used for the high ranking mujtahids whose decrees are followed by the Shi'a people. Such mujtahids arc also known as “marja'” or "Ayatullah''.

Mustahab: recommended, desirable, better. It refers to the acts which are recommended but not wajib. If one neglects them, then he or she will not be punished; however, if one performs them, then he or she will be rewarded. For example: washing hands before eating.

Shari'ah or Shari'a: literally means a way, a stream: in Islamic terminology, it means the laws of Islam.

Sunnat: same as Mustahab. See above.

Wajib: obligatory, necessary, incumbent. An act which must be performed. A person will be rewarded for performing it and punished for neglecting it. For example: the daily prayers.