/lah"dee dah"/ , Informal.
interj.
1. (used as an expression of derision directed at affected gentility or pretentious refinement.)
adj.
2. affected; pretentious; foppish: a la-di-da manner.
n.
3. an affected or pretentious person.
4. behavior or speech characterized by affected or exaggerated gentility.
Also, la-de-da, lah-di-dah .
[ 1880-85; derisive imitation of affected, pseudo-elevated speech ]