SI

1. Spanish for "yes."
2. Misspelling of "is."

1. "I suck." "Si."
2. "NO YUO FAGOT A COMPUTAR SI NOT A HAT!"

by Dj gs68 September 22, 2003

SI

self-injury

I haven't SI'd in two weeks.

by Anonymous Ex-cutter June 21, 2003

SiS

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

John: Aw man SiS
Kevin: Dude I know

by Kife1100 April 5, 2009

SI

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

I.E. billy you fucking si, si does not mean sigh which means you bore.

by jake lowe February 11, 2008

sis

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

sis iud stay in school cuz it's the best

by peter brook August 2, 2008

AS of si

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.

He pulled an AS of SI and nailed all the war bases. What a great player.

by JiggleB January 19, 2017

SI

A term often used when talking about mental health treatment meaning suicidal ideation or suicidal thoughts

My SI had been chilling lately

by Bitchbotch June 22, 2019