A word pronounced with an emphasis on the "green" and key is said sharply. The definition of Green Key is an imaginary object lost to try and talk to a person or start a conversation.
"Mister, I lost my green key?" said Kelly.
"Ah, your green key?" said Austin
"I found your green key." said a girl in the distance
the key to your mind, Marijuana.
John: Yo i'm feeling down man
Chris: use the green key to free yourself man
John: I think i'm gonna be alright.
Chris: <3 no homo