What does the word arra mean in Korean?

The word "arra" doesn't have a specific meaning in Korean. It's possible that you're misremembering the word or that it's a slang term or a word specific to a particular region or dialect.

Could you please provide more context? For example:

* Where did you hear the word? (A conversation, a song, a movie, etc.)

* What was the situation?

* What was the speaker trying to convey?

With more information, I might be able to help you find the correct word or understand the meaning.