Usually used along the lines of "straight up" or "keepin' it real", but it's meaning is inevitably irrelevant. Typically found at the end and separate from the statement that it's used with, or standalone. ya dig? It started as bad pronunciations of numbers 9 and 10 in french.
Girl got booty, NURF DEEZ!
Nacho fries! NURF DEEZ!
"Dude my grandma died 10 minutes ago." "Aw damn.. nurf deez."