Rubaboos is not a common word in English. It may be a made-up word or a very rare word. If someone uses it, you should ask them what it means.
Since rubaboos is not a common word, people might be confused if you use it.
Examples:
I've never heard of rubaboos before.
What does rubaboos mean?
Do you know what rubaboos is?
Rubaboos sounds like a funny word.
I think rubaboos might be a magical creature.
Rubaboos is a strange word to me.