Don't question it Aya. You'll only hurt yourself if you do and still won't come any closer to an answer.

Dejectarine?

The Japanese is "Shonboriiinu". "Shonbori" is an onomatopoeia for being downhearted or piteous, while the "iinu" ending mimics the katakana orthography for names like "Katherine". The portmanteau used here just suggested itself to me, but I'm open to suggestions of alternatives.

Well, it fits with the rest of the silly sound effects of this series.

I'm just curious of the original intent of the word. I don't really get what was being expressed by making it sound like a name.

From what I can see, a lot of what the Osa-Yukus do isn't meant to be understood, just accepted.