add a small amount of black paint to the green paint (if it is paint or liquid of some sort) and mix it well. you can vary the darkness by adding more black paint.
i think its dark green :D
It will make a deep color teal.
very dark green
brown
Brown
Brown
Dark Red (of course)
Viridian (Dark spring green).
Combining green and magenta will produce a dark purple color.
Depending on how dark the green was, the yellow would make the green lighter or it would be absorbed by the dark green as if you didn't mix anything into it. The darker a colour is the harder it is to lighten.
dark or hunter green
its just a disgusting shade of dark green. mix dark blue with it if you want a dark green that doesnt make people depressed.