Green’s Dictionary of Slang

nyamy-nyamy n.

[nyam v.]

(W.I.) a greedy, omnivorous person; thus also as adj.

[WI]L. Bennett Auntie Roachy Sey (2003) 34: An de waistcoat grampa dead lef / Nyamy-nyamy up and tear!
[WI] (ref. to 1940s) L. Bennett Jamaica Labrish 223: nyamy-nyamy. given to eating, gluttonous, disfigured.
[WI]Francis-Jackson Official Dancehall Dict. 37: Nyamy-nyamy gluttonous: u. yuh too nyamy-nyamy.