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!"
by Landoddage May 27, 2009

5 Words Related to Sly Sign

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×