la-di-da
From Longman Dictionary of Contemporary Englishla-di-dala-di-da, lah-di-dah /ˌlɑː diː ˈdɑː/ adjective informal used to describe someone’s behaviour when you think they are talking and behaving as if they consider themselves better than other people SYN snobbish a la-di-da attitudeOrigin la-di-da (1800-1900) Copying the speech of upper-class people