绿灯

绿灯	lǜ dēng	green light (traffic signal) / (fig.) permission to proceed
绿	lù	used in names
绿	lǜ	green / (slang) (derived from 绿帽子) to cheat on (one's spouse or boyfriend or girlfriend)
灯	dēng	lamp / light / lantern / CL:盏