Green’s Dictionary of Slang

1. (US campus) second-rate, insignificant.

1967		Current Sl. I:4 2/2: Weenie, adj. Inferior.
1989		Eble Campus Sl. Mar. 9: weenie cheese – an insult. ‘Stop being such a weenie cheese.’.
2007		W. Ellis Crooked Little Vein 65: You can fly back to where the weenie vanilla straight boys hide.

2. see weeny adj.