Green’s Dictionary of Slang

greeby adj.

[? var. on SE grubby; note grebo n.]

(US teen) ugly, unattractive.

1947		Berrey & Van den Bark Amer. Thes. Sl. (Supplement).
1969		Current Sl. IV:1 9: Greebies, n. Ugly, nasty-looking things [...] Greeby, adj. ugly, nasty-looking.