variants or less commonly la-de-da or lah-de-dah or lah-dee-dah or lah-di-dah
informal
: affectedly or pretentiously elegant or refined in manners or tastes
… they soon became civilized. Two years later Fabyan saw them in Westminster Palace, dressed like la-di-da English courtiers. Samuel Eliot Morison
Iris was a freshman at Climping Academy, the Santa Teresa private school located in Horton Ravine, which was so la-di-da, it totally freaked her out. Sue Grafton