1. A member of any of various Muslim ascetic orders, some of which perform whirling dances and vigorous chanting as acts of ecstatic devotion.
2. One that possesses abundant, often frenzied energy: "[She] is a dervish of unfocused energy, an accident about to happen" (Jane Gross).

[Turkish derviş, mendicant, from Persian darvēsh.]

WORD HISTORY   The word dervish calls to mind the phrases howling dervish and whirling dervish. Certainly there are dervishes whose religious exercises include making loud howling noises or whirling rapidly to induce a dizzy, mystical state. But a dervish is really the Muslim equivalent of a monk or friar, for the Persian word darvēsh, the ultimate source of dervish, means "religious mendicant." The word is first recorded in English in 1585.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.