" ʿālim , active participle of ʿalima , "to know, to be aware of", denotes scholars of almost all disciplines ( lug̲h̲a , bayān , ḥisāb , etc. [q.vv.]). However, the term refers more specifically to the scholars of the religious sciences ( faḳīh , mufassir , muftī , muḥaddit̲h̲ , mutakallim , ḳāriʾ etc. [q.vv.]), considered here exclusively in the context of Sunnism, where they are regarded as the guardians, transmitters and interpreters of religious knowledge, of Islamic doctrine and law; the term also embraces those who fulfil religious functions in the community that require a certain level of expertise in religious and judicial issues, such as judges and preachers ( ḳāḍī , k̲h̲aṭīb [q.vv.]), the imāms of mosques, etc. The ʿālim is often seen as opposed to the adīb , just as religious knowledge ( ʿilm [q.v.]) is clearly distinguished from the practice of "profane literature" ( adab [q.v.])."
Gilliot, Cl., Repp, R.C., Nizami, K.A., Hooker, M.B., Lin, Chang-Kuan and Hunwick, J.O., “ʿUlamāʾ”, in: Encyclopaedia of Islam, Second Edition, Edited by: P. Bearman, Th. Bianquis, C.E. Bosworth, E. van Donzel, W.P. Heinrichs. Consulted online on 17 February 2017