whoop-de-do
From Longman Dictionary of Contemporary Englishwhoop-de-dowhoop-de-do /ˌwuːp diː ˈduː, ˌhuːp-/ interjection American English used to show that you do not think something that someone has told you is as exciting or impressive as they think it is ‘He says he’ll give me a $20 raise.’ ‘Well, whoop-de-do.’Examples from the Corpuswhoop-de-do• "He says he'll give me a $20 raise." "Well, whoop-de-do."Origin whoop-de-do (1900-2000) Perhaps from whoop + to-do