a member of any of various Muslim ascetic orders, as the Sufis, some of which carry on ecstatic observances, such as energetic dancing and whirling or vociferous chanting or shouting.
1585, from Turk. dervish, from Pers. darvesh, darvish "beggar, poor," hence "religious mendicant;" equivalent of Arabic faqir (cf. fakir). The "whirling dervishes" are just one order among many.