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

SI

Sisteme Internacional

SI units are the best, man. Inches suck.

by AnActualDefinition March 12, 2018

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 6, 2022

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

-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 July 7, 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 28, 2011