SiS as in Shit Its Sunday Commonly used on sites like Facebook and Myspace

SI is the abbr. of stupid idiot , although it can also be used in a way in which it means mug

Smirk in Silence:
The act of putting on a straight face after putting someone in a spot.
Pulling someone's leg as a group where everyone acts normal in a scenario that is funny.
Used on social networks, chat rooms and forums..at least could be!

1. Spanish for "yes".

2. Abbreviation for "suck it!"

3. Abreviatiin for "self injury"

suck it slow

stay in school, from peaches song "fuck the pain away"

AS of SI is a clash of clans player that is like a bucket of marshmallows and is as cute as the goji meow stickers he loves. He is commonly referred to as the greatest townhall 9 in CoC. Jew know what I'm saying? He's fiercely loyal to his clan and is irreplaceable. When he's not smashing war bases, he's also the fearless leader of AS123. His mates are lucky to have him.