La-di-da old-fashioned adjective informal
Her la-di-da manner drove me crazy.
All their la-di-da manners explained why I wouldn't trust them.
To behave rudely or impolitely
1. To hold (one) hand and move it up and down.
2. To give (one) a high five.
To act or conduct oneself in an imposing, impressive, resolute, or manly manner or composure
Someone makes an attempt to seem more important, more intelligent, or of a higher class than you really are, usually through their manner, affectation, appearance, or behavior.
To say what other people want or expect to hear
"La-di-da" derives from the earlier reduplicated phrase "lardy-dardy" and was in use by the 1880s.