A common name for either a girl or a boy, usually used in english text like John Doe, Tom Dick and Harry to describe a nameless person but applies to both Male and Female rather than just male."
"Any word on our missing Sam"
"It could be any Sam here."
One who immitates someone in order to impress others specifically copying jokes, personal philosophys and attitudes to life.
"You know that joke i made up yesterday? Well Harry totally did a Greeny to show off to Katie."
"Alfie is doing a Greeny to Impress my ex."