Why are civilian clothes called mufti?: Information Roundup
When a person in military or naval service dons civilian dress (civvies) he is said to be "in mufti." Mufti (pronounced MUFF-tee) in the sense of "plain clothes" as distinguished from a uniform came to us by way of the British army in India. It is an Arabic word literally meaning "magistrate" and is applied specifically in Moslem countries to a chief expounder of Mohammedan law. Formerly the chief judge of Islam at Constantinople was known as the grand mufti. He was the real head of the Mohammedan religion in the Ottoman Empire and, with the body of learned theologians known as ulema, constituted the theocratic element of the Turkish government. The principal Mohammedan judge in any country, district or city was also known as a grand mufti. For instance, the grand mufti of Jerusalem was the head of the Pan-Islamic movement. Strictly speaking, Islam has no church organization, clergy or liturgy, and the muftis are merely highly respected and learned authorities on Moslem law to whom Mohammedan judges of the ecclesiastical courts appeal for expert opinion. Just how mufti acquired the slang or colloquial sense of civilian clothes is not clear. The conventional attire of the Oriental mufti formerly consisted of turban, loose, flowing robes and sandals. In Le Bourgeois Gentilhomme (1670) Molière, the great French writer of comedies, portrayed a mufti on the stage dressed in a plain dressing gown, smoking cap and slippers. It appears that when British officers in India dressed informally their costume was compared to that of the muftis. Later the term came to be applied to any civilian clothes worn by a person who ordinarily wears a military uniform.