Preaching. There are four words generally used for a preacher: khatib , mazakkir , wanz وانز and nasih ناصع.
Khatib is always applied to the official who recites the khutbab, or oration, in the Friday service. The other three terms are applied generally to preachers.
In the present day, preaching seldom takes place in a mosque except on Fridays, when the khutbah is recited, although it is not forbidden, and Muhammad was frequently in the habit of addressing his people after prayers were over.
No Maulawi of reputation preaches in the street, but paid preachers sometimes undertake the office.
Based on Hughes, Dictionary of Islam