Boundless energy. Dervishes are members of a mendicant religious order of Sufi Moslems. Part of their worship is a trance-inducing ritual in which the men, who wear billowing white skirts whirl in circles meant to replicate planets revolving around the sun. “Whirling dervish” became a metaphor for nonstop energy, used in such ways as “He dashed through the hardware store, then ran home and cleaned out the garage and then built shelves along one wall, all before lunch—he was a regular whirling dervish.”