Definition
Hesitance to proceed; limited approval or permission to proceed.
How People Actually Use It
i. When you are not sure if you will be able to do something or not. ii. Something that could be a bit edgey.
"i. Person 1 : "Hey are you coming out to get lashed tonight?" Person 2 : "Hmmm, its going to have to be an amber light for me at the moment, I have lots of work to do and a presentation to prepare for tomorrow." ii. Person 1 : "Man alive, how hot is that girl?" Person 2 : "She's getting an amber light from me at the moment, she could be a bush pig but is too far away to tell.""
Source: Urban Dictionary