A mufti is an Islamic scholar who has the authority to issue legal opinions known as fatawa about fine points of Islamic law. The role of muftis in modern society varies, with Muslim governments typically having an officially appointed mufti who assists the government, while in other areas muftis are far less powerful, although they are still an extremely important community resource for Muslims.
In order to become a mufti, one must obviously be a Muslim, and it is assumed that the mufti is also well educated, just, and of sound mind. Muftis are usually very knowledgeable about the Qu'ran and Hadith, two major authorities for Muslim law, and many are also familiar with legal precedents such as the outcome of court cases and fatawa issued by other muftis. All of these issues are carefully considered when a mufti is asked to give an opinion on an issue.
Muftis can be asked to issue fatawa on a variety of issues. For example, women might be curious about the status of makeup under Muslim law, so they can approach the mufti for an opinion, much like members of the Jewish faith ask rabbis about the fine points of Jewish law. After weighing the evidence, the mufti issues a fatwa which is supposed to be free of political or personal influence, coming solely from established precedent in Muslim law.
While a mufti is a sort of legal authority, it is helpful to remember that fatawa are not legally binding. In fact, muftis may disagree with each other when they issue these legal opinions. Islamic scholars may debate various fatawa with each other in an attempt to come to a decision which respects precedent and the spirit of Islam. By tradition, a fatwa must also cite the authority used to justify it, allowing people to easily look up the relevant information, which can be useful when formulating a response to a fatwa.
A council of muftis is known as a mufiat. The advantage of approaching a mufiat rather than a single mufti is that the resulting fatwa will incorporate decades of experience and training in Islamic law, and it will often be logically and sometimes even beautifully presented and argued. When a mufiat offers advice on a governmental level, it typically includes a number of high profile muftis who are respected scholarly figures in their communities and abroad.