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

SI

Sisteme Internacional

SI units are the best, man. Inches suck.

by AnActualDefinition March 12, 2018

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

SIS

Typical abbreviation for the Saying "Slaves in shackles", Racist.

"Don't do that sis" (Don't do that, slave in shackles" "are you a sis?" (Are you a slave in shackles?)

by Educational Institutions January 7, 2022

-sies

A suffix added to any noun meant to accentuate the word in the sentence. Manages to get very annoying.

"Let's go and get dome drinksies."

"Crazy wetness in the poolsies!"

by The Allergen June 27, 2005

si

Abbr. Simple Simon. Individual renowned for extreme stupidity and slowness of mind.

"Jog on you si - you're as thick as pigshit" or "he's a proper si that one, thicker than a King Edward yoghurt"

by Phileas May 20, 2008

SIS

acronym for snicker inside - use instead of LOL when describing what one is actually doing when one chats/texts.

person a: I blacked out last night and lost my pants.
person b: SIS. You friend, are unpredictable.

by omniv0re December 26, 2011