What is Sly Sign?
1.
When you put your middle finger up to somebody behind an opaque object (predominantly a door), releasing anger but not getting into trouble. Usually used by young teens, aimed at parents.
"My mom was being so annoying... so i sly signed her through the door when i left the room."
"No way dude!"
See
Random Words:
1.
Someone who works on aircraft and sits in the cockpit pretending to fly, because they cant become a pilotfor some reason.
Also see gara..
