Used as a completely random response for when you can't think of anything.
Also used as a response for when someone is very very lightly annoyed about something.
This is a completely random word, so the meaning is very much dependent on how you use it (
like with a lot of words). There isn't really a set
definition, this is a
loose framing of how I've used the word so far, and thus the meaning it has.
"Every time I wake up and look at my
phone, there are so many messages about
sugar and
salt..."
"Yumpa."
"You wanna explain why I'm seeing five watermelons in the kitchen?"
"Yumpa yumpa."