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.
To be satisfied with past achievements and stop trying to achieve something new..
If you rest on your laurels, you will fall behind others.