doolally

The story

From doolally tap (“camp fever; (by extension) eccentricity; madness”), with doolally interpreted as an adjective. Doolally is derived from the Deolali transit camp, a former British army camp about 100 miles (160 kilometres) northeast of Bombay, India, used as a transit station for soldiers awaiting transport back to Britain; while tap (“Indian malarial fever”) is from Persian or Urdu تب (tab, “malarial fever”), ultimately from Sanskrit ताप (tāpa, “fever; heat; pain, torment”).