It's a slang word used to say something is awesome or astounding. It can also be doubled or even tripled as "Up Up Up" to stress or lay more emphasis on the awesomeness of the idea or thing in question.
Patois: Up Up...mi neva did know seh a suh nice him coulda dweet!
English: Awesome...I never knew that's how nice he could do it.
Looking for a quick and easy way to learn Jamaican Patois? Our Beginner's Guide has everything you need to get started;