Definition of yada yada in US English:

yada yada

exclamation

US
informal
  • Indicating (usually dismissively) that further details are predictable or evident from what has preceded: ‘and so on’, ‘blah blah blah’.

noun

US
informal
  • Trivial, meaningless, or uninteresting talk or writing; chatter.

Origin

1960s. Imitative of the sound of human speech, probably influenced by (or perhaps an alteration of) yatter.