Subscribe English look up any word, like blastoising: 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 9 0  Words related to Sly Sign:  sign signing sly slying
slysign