doolally tap

Meanings

Noun

• Camp fever; by extension, madness, eccentricity.

Adjective

• Mad, insane, eccentric.

Origin

• From Deolali (the name of a former British army camp 100 miles north-east of Bombay, used as a transit station for soldiers awaiting transport back to Britain) + tap (from Persian or Urdu تب ("malarial fever"), ultimately from Sanskrit ताप ("heat; fever")).
• 
  According to one theory, to go doolally tap was to go crazy waiting.