Opposes Greens (5)
I believe the answer is:
bucks
This might be a double definition.
'opposes' is the first definition.
(bucking is a kind of opposing)
'greens' is the second definition.
Although both the answer and definition are verbs in their -s form, I can't see how one could define the other.
Can you help me to learn more?
(Other definitions for bucks that I've seen before include "Dollars" , "dandies" , "Goes against" , "young men" , "Resists" .)