1. temporarily deranged or feeble-minded: informalBritish"Uncle's gone doolally again"
▪ transported with excitement or pleasure:informalBritish"a return on capital that the City would go doolally over"
Word Originearly 20th century: originally doolally tap, Indian army slang, from Deolali (the name of a town with a military sanatorium and a transit camp) + Urdu tap ‘fever’.