It's a polite way to express gratitude for someone's effort or work.
Here's a breakdown:
* Ku: This is a shortened form of "E ku" which means "Thank you".
* ise: This means "work" or "effort".
* oo: This is an exclamation particle, adding emphasis to the phrase.
So, "Ku ise oo" is a way to show appreciation for someone's hard work or dedication.