give somebody/get the green light
get the green light
To receive permission to proceed with some action or task. Likened to the green light of a traffic signal. We're just waiting to get the green light from our managers before we release the latest software update.
give somebody/get the ˌgreen ˈlight(informal) allow somebody/be allowed to begin something: The council has given the green light for work to begin on the new shopping centre. ♢ As soon as we get the green light, we’ll start advertising for new staff.
This expression refers to the green light on traffic lights, which means ‘go’.