開綠燈

to give the green light / to give the go-ahead

to open / to start / to turn on / to boil / to write out (a prescription, check, invoice etc) / to operate (a vehicle) / carat (gold) / abbr. for Kelvin, 開爾文|开尔文[Kai1 er3 wen2] / abbr. for 開本|开本[kai1 ben3], book format

green / (slang) (derived from 綠帽子|绿帽子[lü4 mao4 zi5]) to cheat on (one's spouse or boyfriend or girlfriend)

green light (traffic signal) / (fig.) permission to proceed

lamp / light / lantern / CL:盞|盏[zhan3]